Merge branch 'master' of https://github.com/grpc/grpc into channelz-cpp-server

.clang-tidy

@@ -1,6 +1,6 @@
 ---
-Checks: 'modernize-use-nullptr,google-build-namespaces,google-build-explicit-make-pair,readability-function-size,performance-*'
-WarningsAsErrors: 'modernize-use-nullptr,google-build-namespaces,google-build-explicit-make-pair,readability-function-size,performance-*'
+Checks: 'modernize-use-nullptr,google-build-namespaces,google-build-explicit-make-pair,readability-function-size,performance-*,bugprone-*'
+WarningsAsErrors: 'modernize-use-nullptr,google-build-namespaces,google-build-explicit-make-pair,readability-function-size,performance-*,bugprone-*'
 CheckOptions:
   - key:    readability-function-size.StatementThreshold
     value:  '450'

BUILDING.md

@@ -132,8 +132,8 @@ you will be able to browse and build the code.
 > @rem Run from grpc directory after cloning the repo with --recursive or updating submodules.
 > md .build
 > cd .build
-> cmake .. -G "Visual Studio 14 2015" -DCMAKE_BUILD_TYPE=Release
-> cmake --build .
+> cmake .. -G "Visual Studio 14 2015"
+> cmake --build . --config Release
 ```
 
 ## cmake: Windows, Using Ninja (faster build, supports boringssl's assembly optimizations).

bazel/grpc_build_system.bzl

@@ -24,178 +24,203 @@
 #
 
 # The set of pollers to test against if a test exercises polling
-POLLERS = ['epollex', 'epollsig', 'epoll1', 'poll', 'poll-cv']
+POLLERS = ["epollex", "epollsig", "epoll1", "poll", "poll-cv"]
 
 def if_not_windows(a):
-  return select({
-      "//:windows": [],
-      "//:windows_msvc": [],
-      "//conditions:default": a,
-  })
+    return select({
+        "//:windows": [],
+        "//:windows_msvc": [],
+        "//conditions:default": a,
+    })
 
 def _get_external_deps(external_deps):
-  ret = []
-  for dep in external_deps:
-    if dep == "address_sorting":
-      ret += ["//third_party/address_sorting"]
-    elif dep == "cares":
-      ret += select({"//:grpc_no_ares": [],
-                     "//conditions:default": ["//external:cares"],})
-    else:
-      ret += ["//external:" + dep]
-  return ret
+    ret = []
+    for dep in external_deps:
+        if dep == "address_sorting":
+            ret += ["//third_party/address_sorting"]
+        elif dep == "cares":
+            ret += select({
+                "//:grpc_no_ares": [],
+                "//conditions:default": ["//external:cares"],
+            })
+        else:
+            ret += ["//external:" + dep]
+    return ret
 
 def _maybe_update_cc_library_hdrs(hdrs):
-  ret = []
-  hdrs_to_update = {
-      "third_party/objective_c/Cronet/bidirectional_stream_c.h": "//third_party:objective_c/Cronet/bidirectional_stream_c.h",
-  }
-  for h in hdrs:
-    if h in hdrs_to_update.keys():
-      ret.append(hdrs_to_update[h])
-    else:
-      ret.append(h)
-  return ret
-
-def grpc_cc_library(name, srcs = [], public_hdrs = [], hdrs = [],
-                    external_deps = [], deps = [], standalone = False,
-                    language = "C++", testonly = False, visibility = None,
-                    alwayslink = 0, data = []):
-  copts = []
-  if language.upper() == "C":
-    copts = if_not_windows(["-std=c99"])
-  native.cc_library(
-    name = name,
-    srcs = srcs,
-    defines = select({"//:grpc_no_ares": ["GRPC_ARES=0"],
-                      "//conditions:default": [],}) +
-              select({"//:remote_execution":  ["GRPC_PORT_ISOLATED_RUNTIME=1"],
-                      "//conditions:default": [],}) +
-              select({"//:grpc_allow_exceptions":  ["GRPC_ALLOW_EXCEPTIONS=1"],
-                      "//:grpc_disallow_exceptions":
-                      ["GRPC_ALLOW_EXCEPTIONS=0"],
-                      "//conditions:default": [],}),
-    hdrs = _maybe_update_cc_library_hdrs(hdrs + public_hdrs),
-    deps = deps + _get_external_deps(external_deps),
-    copts = copts,
-    visibility = visibility,
-    testonly = testonly,
-    linkopts = if_not_windows(["-pthread"]),
-    includes = [
-        "include"
-    ],
-    alwayslink = alwayslink,
-    data = data,
-  )
+    ret = []
+    hdrs_to_update = {
+        "third_party/objective_c/Cronet/bidirectional_stream_c.h": "//third_party:objective_c/Cronet/bidirectional_stream_c.h",
+    }
+    for h in hdrs:
+        if h in hdrs_to_update.keys():
+            ret.append(hdrs_to_update[h])
+        else:
+            ret.append(h)
+    return ret
+
+def grpc_cc_library(
+        name,
+        srcs = [],
+        public_hdrs = [],
+        hdrs = [],
+        external_deps = [],
+        deps = [],
+        standalone = False,
+        language = "C++",
+        testonly = False,
+        visibility = None,
+        alwayslink = 0,
+        data = []):
+    copts = []
+    if language.upper() == "C":
+        copts = if_not_windows(["-std=c99"])
+    native.cc_library(
+        name = name,
+        srcs = srcs,
+        defines = select({
+                      "//:grpc_no_ares": ["GRPC_ARES=0"],
+                      "//conditions:default": [],
+                  }) +
+                  select({
+                      "//:remote_execution": ["GRPC_PORT_ISOLATED_RUNTIME=1"],
+                      "//conditions:default": [],
+                  }) +
+                  select({
+                      "//:grpc_allow_exceptions": ["GRPC_ALLOW_EXCEPTIONS=1"],
+                      "//:grpc_disallow_exceptions": ["GRPC_ALLOW_EXCEPTIONS=0"],
+                      "//conditions:default": [],
+                  }),
+        hdrs = _maybe_update_cc_library_hdrs(hdrs + public_hdrs),
+        deps = deps + _get_external_deps(external_deps),
+        copts = copts,
+        visibility = visibility,
+        testonly = testonly,
+        linkopts = if_not_windows(["-pthread"]),
+        includes = [
+            "include",
+        ],
+        alwayslink = alwayslink,
+        data = data,
+    )
 
 def grpc_proto_plugin(name, srcs = [], deps = []):
-  native.cc_binary(
-    name = name,
-    srcs = srcs,
-    deps = deps,
-  )
+    native.cc_binary(
+        name = name,
+        srcs = srcs,
+        deps = deps,
+    )
 
 load("//:bazel/cc_grpc_library.bzl", "cc_grpc_library")
 
-def grpc_proto_library(name, srcs = [], deps = [], well_known_protos = False,
-                       has_services = True, use_external = False, generate_mocks = False):
-  cc_grpc_library(
-    name = name,
-    srcs = srcs,
-    deps = deps,
-    well_known_protos = well_known_protos,
-    proto_only = not has_services,
-    use_external = use_external,
-    generate_mocks = generate_mocks,
-  )
+def grpc_proto_library(
+        name,
+        srcs = [],
+        deps = [],
+        well_known_protos = False,
+        has_services = True,
+        use_external = False,
+        generate_mocks = False):
+    cc_grpc_library(
+        name = name,
+        srcs = srcs,
+        deps = deps,
+        well_known_protos = well_known_protos,
+        proto_only = not has_services,
+        use_external = use_external,
+        generate_mocks = generate_mocks,
+    )
 
 def grpc_cc_test(name, srcs = [], deps = [], external_deps = [], args = [], data = [], uses_polling = True, language = "C++", size = "medium", timeout = "moderate", tags = []):
-  copts = []
-  if language.upper() == "C":
-    copts = if_not_windows(["-std=c99"])
-  args = {
-    'name': name,
-    'srcs': srcs,
-    'args': args,
-    'data': data,
-    'deps': deps + _get_external_deps(external_deps),
-    'copts': copts,
-    'linkopts': if_not_windows(["-pthread"]),
-    'size': size,
-    'timeout': timeout,
-  }
-  if uses_polling:
-    native.cc_test(testonly=True, tags=['manual'], **args)
-    for poller in POLLERS:
-      native.sh_test(
-        name = name + '@poller=' + poller,
-        data = [name],
-        srcs = [
-          '//test/core/util:run_with_poller_sh',
-        ],
-        size = size,
-        timeout = timeout,
-        args = [
-          poller,
-          '$(location %s)' % name,
-        ] + args['args'],
-        tags = tags,
-      )
-  else:
-    native.cc_test(**args)
+    copts = []
+    if language.upper() == "C":
+        copts = if_not_windows(["-std=c99"])
+    args = {
+        "name": name,
+        "srcs": srcs,
+        "args": args,
+        "data": data,
+        "deps": deps + _get_external_deps(external_deps),
+        "copts": copts,
+        "linkopts": if_not_windows(["-pthread"]),
+        "size": size,
+        "timeout": timeout,
+    }
+    if uses_polling:
+        native.cc_test(testonly = True, tags = ["manual"], **args)
+        for poller in POLLERS:
+            native.sh_test(
+                name = name + "@poller=" + poller,
+                data = [name] + data,
+                srcs = [
+                    "//test/core/util:run_with_poller_sh",
+                ],
+                size = size,
+                timeout = timeout,
+                args = [
+                    poller,
+                    "$(location %s)" % name,
+                ] + args["args"],
+                tags = tags,
+            )
+    else:
+        native.cc_test(**args)
 
 def grpc_cc_binary(name, srcs = [], deps = [], external_deps = [], args = [], data = [], language = "C++", testonly = False, linkshared = False, linkopts = []):
-  copts = []
-  if language.upper() == "C":
-    copts = ["-std=c99"]
-  native.cc_binary(
-    name = name,
-    srcs = srcs,
-    args = args,
-    data = data,
-    testonly = testonly,
-    linkshared = linkshared,
-    deps = deps + _get_external_deps(external_deps),
-    copts = copts,
-    linkopts = if_not_windows(["-pthread"]) + linkopts,
-  )
-
-def grpc_generate_one_off_targets(): pass
+    copts = []
+    if language.upper() == "C":
+        copts = ["-std=c99"]
+    native.cc_binary(
+        name = name,
+        srcs = srcs,
+        args = args,
+        data = data,
+        testonly = testonly,
+        linkshared = linkshared,
+        deps = deps + _get_external_deps(external_deps),
+        copts = copts,
+        linkopts = if_not_windows(["-pthread"]) + linkopts,
+    )
+
+def grpc_generate_one_off_targets():
+    pass
 
 def grpc_sh_test(name, srcs, args = [], data = []):
-  native.sh_test(
-    name = name,
-    srcs = srcs,
-    args = args,
-    data = data)
+    native.sh_test(
+        name = name,
+        srcs = srcs,
+        args = args,
+        data = data,
+    )
 
 def grpc_sh_binary(name, srcs, data = []):
-  native.sh_binary(
-    name = name,
-    srcs = srcs,
-    data = data)
+    native.sh_binary(
+        name = name,
+        srcs = srcs,
+        data = data,
+    )
 
 def grpc_py_binary(name, srcs, data = [], deps = [], external_deps = [], testonly = False):
-  native.py_binary(
-    name = name,
-    srcs = srcs,
-    testonly = testonly,
-    data = data,
-    deps = deps + _get_external_deps(external_deps)
-  )
+    native.py_binary(
+        name = name,
+        srcs = srcs,
+        testonly = testonly,
+        data = data,
+        deps = deps + _get_external_deps(external_deps),
+    )
 
 def grpc_package(name, visibility = "private", features = []):
-  if visibility == "tests":
-    visibility = ["//test:__subpackages__"]
-  elif visibility == "public":
-    visibility = ["//visibility:public"]
-  elif visibility == "private":
-    visibility = []
-  else:
-    fail("Unknown visibility " + visibility)
-
-  if len(visibility) != 0:
-    native.package(
-      default_visibility = visibility,
-      features = features
-    )
+    if visibility == "tests":
+        visibility = ["//test:__subpackages__"]
+    elif visibility == "public":
+        visibility = ["//visibility:public"]
+    elif visibility == "private":
+        visibility = []
+    else:
+        fail("Unknown visibility " + visibility)
+
+    if len(visibility) != 0:
+        native.package(
+            default_visibility = visibility,
+            features = features,
+        )

examples/csharp/Helloworld/Greeter/Greeter.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>Greeter</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>Greeter</AssemblyName>
     <PackageId>Greeter</PackageId>

examples/csharp/Helloworld/GreeterClient/GreeterClient.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>GreeterClient</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>GreeterClient</AssemblyName>
     <OutputType>Exe</OutputType>

examples/csharp/Helloworld/GreeterServer/GreeterServer.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>GreeterServer</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>GreeterServer</AssemblyName>
     <OutputType>Exe</OutputType>

examples/csharp/Helloworld/README.md

@@ -12,7 +12,7 @@ which have been already added to the project for you.
 PREREQUISITES
 -------------
 
-- The [.NET Core SDK](https://www.microsoft.com/net/core) (version 2+ is recommended)
+- The [.NET Core SDK 2.1+](https://www.microsoft.com/net/core)
 
 You can also build the example directly using Visual Studio 2017, but it's not a requirement.
 
@@ -23,8 +23,6 @@ From the `examples/csharp/Helloworld` directory:
 
 - `dotnet build Greeter.sln`
 
-(if you're using dotnet SDK 1.x you need to run `dotnet restore Greeter.sln` first)
-
 Try it!
 -------
 
@@ -32,14 +30,14 @@ Try it!
 
   ```
   > cd GreeterServer
-  > dotnet run -f netcoreapp1.0
+  > dotnet run -f netcoreapp2.1
   ```
 
 - Run the client
 
   ```
   > cd GreeterClient
-  > dotnet run -f netcoreapp1.0
+  > dotnet run -f netcoreapp2.1
   ```
 
 Tutorial

examples/csharp/RouteGuide/RouteGuide/RouteGuide.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>RouteGuide</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>RouteGuide</AssemblyName>
     <PackageId>RouteGuide</PackageId>

examples/csharp/RouteGuide/RouteGuideClient/RouteGuideClient.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>RouteGuideClient</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>RouteGuideClient</AssemblyName>
     <OutputType>Exe</OutputType>

examples/csharp/RouteGuide/RouteGuideServer/RouteGuideServer.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <AssemblyTitle>RouteGuideServer</AssemblyTitle>
-    <TargetFrameworks>netcoreapp1.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.1</TargetFrameworks>
     <DebugType>portable</DebugType>
     <AssemblyName>RouteGuideServer</AssemblyName>
     <OutputType>Exe</OutputType>

include/grpc/grpc_security_constants.h

@@ -57,46 +57,51 @@ typedef enum {
 } grpc_ssl_certificate_config_reload_status;
 
 typedef enum {
-  /** Server does not request client certificate. A client can present a self
-     signed or signed certificates if it wishes to do so and they would be
-     accepted. */
+  /** Server does not request client certificate.
+     The certificate presented by the client is not checked by the server at
+     all. (A client may present a self signed or signed certificate or not
+     present a certificate at all and any of those option would be accepted) */
   GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE,
   /** Server requests client certificate but does not enforce that the client
      presents a certificate.
 
      If the client presents a certificate, the client authentication is left to
-     the application based on the metadata like certificate etc.
+     the application (the necessary metadata will be available to the
+     application via authentication context properties, see grpc_auth_context).
 
-     The key cert pair should still be valid for the SSL connection to be
-     established. */
+     The client's key certificate pair must be valid for the SSL connection to
+     be established. */
   GRPC_SSL_REQUEST_CLIENT_CERTIFICATE_BUT_DONT_VERIFY,
   /** Server requests client certificate but does not enforce that the client
      presents a certificate.
 
      If the client presents a certificate, the client authentication is done by
-     grpc framework (The client needs to either present a signed cert or skip no
-     certificate for a successful connection).
+     the gRPC framework. (For a successful connection the client needs to either
+     present a certificate that can be verified against the root certificate
+     configured by the server or not present a certificate at all)
 
-     The key cert pair should still be valid for the SSL connection to be
-     established. */
+     The client's key certificate pair must be valid for the SSL connection to
+     be established. */
   GRPC_SSL_REQUEST_CLIENT_CERTIFICATE_AND_VERIFY,
-  /** Server requests client certificate but enforces that the client presents a
+  /** Server requests client certificate and enforces that the client presents a
      certificate.
 
      If the client presents a certificate, the client authentication is left to
-     the application based on the metadata like certificate etc.
+     the application (the necessary metadata will be available to the
+     application via authentication context properties, see grpc_auth_context).
 
-     The key cert pair should still be valid for the SSL connection to be
-     established. */
+     The client's key certificate pair must be valid for the SSL connection to
+     be established. */
   GRPC_SSL_REQUEST_AND_REQUIRE_CLIENT_CERTIFICATE_BUT_DONT_VERIFY,
-  /** Server requests client certificate but enforces that the client presents a
+  /** Server requests client certificate and enforces that the client presents a
      certificate.
 
-     The cerificate presented by the client is verified by grpc framework (The
-     client needs to present signed certs for a successful connection).
+     The cerificate presented by the client is verified by the gRPC framework.
+     (For a successful connection the client needs to present a certificate that
+     can be verified against the root certificate configured by the server)
 
-     The key cert pair should still be valid for the SSL connection to be
-     established. */
+     The client's key certificate pair must be valid for the SSL connection to
+     be established. */
   GRPC_SSL_REQUEST_AND_REQUIRE_CLIENT_CERTIFICATE_AND_VERIFY
 } grpc_ssl_client_certificate_request_type;
 

include/grpc/impl/codegen/grpc_types.h

@@ -342,6 +342,9 @@ typedef struct {
   "grpc.disable_client_authority_filter"
 /** If set to zero, disables use of http proxies. Enabled by default. */
 #define GRPC_ARG_ENABLE_HTTP_PROXY "grpc.enable_http_proxy"
+/** If set to non zero, surfaces the user agent string to the server. User
+    agent is surfaced by default. */
+#define GRPC_ARG_SURFACE_USER_AGENT "grpc.surface_user_agent"
 /** \} */
 
 /** Result of a grpc call. If the caller satisfies the prerequisites of a

include/grpcpp/impl/codegen/async_stream.h

@@ -195,6 +195,13 @@ class ClientAsyncReader final : public ClientAsyncReaderInterface<R> {
     assert(size == sizeof(ClientAsyncReader));
   }
 
+  // This operator should never be called as the memory should be freed as part
+  // of the arena destruction. It only exists to provide a matching operator
+  // delete to the operator new so that some compilers will not complain (see
+  // https://github.com/grpc/grpc/issues/11301) Note at the time of adding this
+  // there are no tests catching the compiler warning.
+  static void operator delete(void*, void*) { assert(0); }
+
   void StartCall(void* tag) override {
     assert(!started_);
     started_ = true;
@@ -336,6 +343,13 @@ class ClientAsyncWriter final : public ClientAsyncWriterInterface<W> {
     assert(size == sizeof(ClientAsyncWriter));
   }
 
+  // This operator should never be called as the memory should be freed as part
+  // of the arena destruction. It only exists to provide a matching operator
+  // delete to the operator new so that some compilers will not complain (see
+  // https://github.com/grpc/grpc/issues/11301) Note at the time of adding this
+  // there are no tests catching the compiler warning.
+  static void operator delete(void*, void*) { assert(0); }
+
   void StartCall(void* tag) override {
     assert(!started_);
     started_ = true;
@@ -496,6 +510,13 @@ class ClientAsyncReaderWriter final
     assert(size == sizeof(ClientAsyncReaderWriter));
   }
 
+  // This operator should never be called as the memory should be freed as part
+  // of the arena destruction. It only exists to provide a matching operator
+  // delete to the operator new so that some compilers will not complain (see
+  // https://github.com/grpc/grpc/issues/11301) Note at the time of adding this
+  // there are no tests catching the compiler warning.
+  static void operator delete(void*, void*) { assert(0); }
+
   void StartCall(void* tag) override {
     assert(!started_);
     started_ = true;

include/grpcpp/impl/codegen/call.h

@@ -50,8 +50,6 @@ namespace internal {
 class Call;
 class CallHook;
 
-const char kBinaryErrorDetailsKey[] = "grpc-status-details-bin";
-
 // TODO(yangg) if the map is changed before we send, the pointers will be a
 // mess. Make sure it does not happen.
 inline grpc_metadata* FillMetadataArray(
@@ -531,7 +529,6 @@ class CallOpRecvInitialMetadata {
 
   void FinishOp(bool* status) {
     if (metadata_map_ == nullptr) return;
-    metadata_map_->FillMap();
     metadata_map_ = nullptr;
   }
 
@@ -566,13 +563,7 @@ class CallOpClientRecvStatus {
 
   void FinishOp(bool* status) {
     if (recv_status_ == nullptr) return;
-    metadata_map_->FillMap();
-    grpc::string binary_error_details;
-    auto iter = metadata_map_->map()->find(kBinaryErrorDetailsKey);
-    if (iter != metadata_map_->map()->end()) {
-      binary_error_details =
-          grpc::string(iter->second.begin(), iter->second.length());
-    }
+    grpc::string binary_error_details = metadata_map_->GetBinaryErrorDetails();
     *recv_status_ =
         Status(static_cast<StatusCode>(status_code_),
                GRPC_SLICE_IS_EMPTY(error_message_)

include/grpcpp/impl/codegen/client_context.h

@@ -425,8 +425,8 @@ class ClientContext {
   mutable std::shared_ptr<const AuthContext> auth_context_;
   struct census_context* census_context_;
   std::multimap<grpc::string, grpc::string> send_initial_metadata_;
-  internal::MetadataMap recv_initial_metadata_;
-  internal::MetadataMap trailing_metadata_;
+  mutable internal::MetadataMap recv_initial_metadata_;
+  mutable internal::MetadataMap trailing_metadata_;
 
   grpc_call* propagate_from_call_;
   PropagationOptions propagation_options_;

include/grpcpp/impl/codegen/metadata_map.h

@@ -19,11 +19,15 @@
 #ifndef GRPCPP_IMPL_CODEGEN_METADATA_MAP_H
 #define GRPCPP_IMPL_CODEGEN_METADATA_MAP_H
 
+#include <grpc/impl/codegen/log.h>
 #include <grpcpp/impl/codegen/slice.h>
 
 namespace grpc {
 
 namespace internal {
+
+const char kBinaryErrorDetailsKey[] = "grpc-status-details-bin";
+
 class MetadataMap {
  public:
   MetadataMap() { memset(&arr_, 0, sizeof(arr_)); }
@@ -32,24 +36,54 @@ class MetadataMap {
     g_core_codegen_interface->grpc_metadata_array_destroy(&arr_);
   }
 
-  void FillMap() {
-    for (size_t i = 0; i < arr_.count; i++) {
-      // TODO(yangg) handle duplicates?
-      map_.insert(std::pair<grpc::string_ref, grpc::string_ref>(
-          StringRefFromSlice(&arr_.metadata[i].key),
-          StringRefFromSlice(&arr_.metadata[i].value)));
+  grpc::string GetBinaryErrorDetails() {
+    // if filled_, extract from the multimap for O(log(n))
+    if (filled_) {
+      auto iter = map_.find(kBinaryErrorDetailsKey);
+      if (iter != map_.end()) {
+        return grpc::string(iter->second.begin(), iter->second.length());
+      }
+    }
+    // if not yet filled, take the O(n) lookup to avoid allocating the
+    // multimap until it is requested.
+    // TODO(ncteisen): plumb this through core as a first class object, just
+    // like code and message.
+    else {
+      for (size_t i = 0; i < arr_.count; i++) {
+        if (strncmp(reinterpret_cast<const char*>(
+                        GRPC_SLICE_START_PTR(arr_.metadata[i].key)),
+                    kBinaryErrorDetailsKey,
+                    GRPC_SLICE_LENGTH(arr_.metadata[i].key)) == 0) {
+          return grpc::string(reinterpret_cast<const char*>(
+                                  GRPC_SLICE_START_PTR(arr_.metadata[i].value)),
+                              GRPC_SLICE_LENGTH(arr_.metadata[i].value));
+        }
+      }
     }
+    return grpc::string();
   }
 
-  std::multimap<grpc::string_ref, grpc::string_ref>* map() { return &map_; }
-  const std::multimap<grpc::string_ref, grpc::string_ref>* map() const {
+  std::multimap<grpc::string_ref, grpc::string_ref>* map() {
+    FillMap();
     return &map_;
   }
   grpc_metadata_array* arr() { return &arr_; }
 
  private:
+  bool filled_ = false;
   grpc_metadata_array arr_;
   std::multimap<grpc::string_ref, grpc::string_ref> map_;
+
+  void FillMap() {
+    if (filled_) return;
+    filled_ = true;
+    for (size_t i = 0; i < arr_.count; i++) {
+      // TODO(yangg) handle duplicates?
+      map_.insert(std::pair<grpc::string_ref, grpc::string_ref>(
+          StringRefFromSlice(&arr_.metadata[i].key),
+          StringRefFromSlice(&arr_.metadata[i].value)));
+    }
+  }
 };
 }  // namespace internal
 

include/grpcpp/impl/codegen/server_context.h

@@ -294,7 +294,7 @@ class ServerContext {
   CompletionQueue* cq_;
   bool sent_initial_metadata_;
   mutable std::shared_ptr<const AuthContext> auth_context_;
-  internal::MetadataMap client_metadata_;
+  mutable internal::MetadataMap client_metadata_;
   std::multimap<grpc::string, grpc::string> initial_metadata_;
   std::multimap<grpc::string, grpc::string> trailing_metadata_;
 

src/core/ext/filters/client_channel/client_channel.cc

@@ -457,7 +457,6 @@ get_service_config_from_resolver_result_locked(channel_data* chand) {
         grpc_uri* uri = grpc_uri_parse(server_uri, true);
         GPR_ASSERT(uri->path[0] != '\0');
         service_config_parsing_state parsing_state;
-        memset(&parsing_state, 0, sizeof(parsing_state));
         parsing_state.server_name =
             uri->path[0] == '/' ? uri->path + 1 : uri->path;
         service_config->ParseGlobalParams(parse_retry_throttle_params,
@@ -937,7 +936,7 @@ typedef struct client_channel_call_data {
   // state needed to support channelz interception of recv trailing metadata.
   grpc_closure recv_trailing_metadata_ready_channelz;
   grpc_closure* original_recv_trailing_metadata;
-  grpc_transport_stream_op_batch* recv_trailing_metadata_batch;
+  grpc_metadata_batch* recv_trailing_metadata;
 
   grpc_polling_entity* pollent;
   bool pollent_added_to_interested_parties;
@@ -1000,14 +999,8 @@ static void start_internal_recv_trailing_metadata(grpc_call_element* elem);
 static void on_complete(void* arg, grpc_error* error);
 static void start_retriable_subchannel_batches(void* arg, grpc_error* ignored);
 static void start_pick_locked(void* arg, grpc_error* ignored);
-template <typename Predicate>
-static pending_batch* pending_batch_find(grpc_call_element* elem,
-                                         const char* log_message,
-                                         Predicate predicate);
-static void get_call_status(grpc_call_element* elem,
-                            grpc_metadata_batch* md_batch, grpc_error* error,
-                            grpc_status_code* status,
-                            grpc_mdelem** server_pushback_md);
+static void maybe_intercept_recv_trailing_metadata_for_channelz(
+    grpc_call_element* elem, grpc_transport_stream_op_batch* batch);
 
 //
 // send op data caching
@@ -1282,66 +1275,6 @@ static void resume_pending_batch_in_call_combiner(void* arg,
   grpc_subchannel_call_process_op(subchannel_call, batch);
 }
 
-static void recv_trailing_metadata_ready_channelz(void* arg,
-                                                  grpc_error* error) {
-  grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO,
-            "chand=%p calld=%p: got recv_trailing_metadata_ready_channelz, "
-            "error=%s",
-            chand, calld, grpc_error_string(error));
-  }
-  GPR_ASSERT(calld->recv_trailing_metadata_batch != nullptr);
-  grpc_status_code status = GRPC_STATUS_OK;
-  grpc_metadata_batch* md_batch =
-      calld->recv_trailing_metadata_batch->payload->recv_trailing_metadata
-          .recv_trailing_metadata;
-  get_call_status(elem, md_batch, GRPC_ERROR_REF(error), &status, nullptr);
-  grpc_core::channelz::SubchannelNode* channelz_subchannel =
-      calld->pick.connected_subchannel->channelz_subchannel();
-  GPR_ASSERT(channelz_subchannel != nullptr);
-  if (status == GRPC_STATUS_OK) {
-    channelz_subchannel->RecordCallSucceeded();
-  } else {
-    channelz_subchannel->RecordCallFailed();
-  }
-  calld->recv_trailing_metadata_batch = nullptr;
-  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata, error);
-}
-
-// If channelz is enabled, intercept recv_trailing so that we may check the
-// status and associate it to a subchannel.
-// Returns true if callback was intercepted, false otherwise.
-static void maybe_intercept_recv_trailing_for_channelz(
-    grpc_call_element* elem, grpc_transport_stream_op_batch* batch) {
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  // only intercept payloads with recv trailing.
-  if (!batch->recv_trailing_metadata) {
-    return;
-  }
-  // only add interceptor is channelz is enabled.
-  if (calld->pick.connected_subchannel->channelz_subchannel() == nullptr) {
-    return;
-  }
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO,
-            "calld=%p batch=%p: intercepting recv trailing for channelz", calld,
-            batch);
-  }
-  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready_channelz,
-                    recv_trailing_metadata_ready_channelz, elem,
-                    grpc_schedule_on_exec_ctx);
-  // save some state needed for the interception callback.
-  GPR_ASSERT(calld->recv_trailing_metadata_batch == nullptr);
-  calld->recv_trailing_metadata_batch = batch;
-  calld->original_recv_trailing_metadata =
-      batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
-  batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
-      &calld->recv_trailing_metadata_ready_channelz;
-}
-
 // This is called via the call combiner, so access to calld is synchronized.
 static void pending_batches_resume(grpc_call_element* elem) {
   channel_data* chand = static_cast<channel_data*>(elem->channel_data);
@@ -1366,7 +1299,7 @@ static void pending_batches_resume(grpc_call_element* elem) {
     pending_batch* pending = &calld->pending_batches[i];
     grpc_transport_stream_op_batch* batch = pending->batch;
     if (batch != nullptr) {
-      maybe_intercept_recv_trailing_for_channelz(elem, batch);
+      maybe_intercept_recv_trailing_metadata_for_channelz(elem, batch);
       batch->handler_private.extra_arg = calld->subchannel_call;
       GRPC_CLOSURE_INIT(&batch->handler_private.closure,
                         resume_pending_batch_in_call_combiner, batch,
@@ -2656,6 +2589,69 @@ static void start_retriable_subchannel_batches(void* arg, grpc_error* ignored) {
   closures.RunClosures(calld->call_combiner);
 }
 
+//
+// Channelz
+//
+
+static void recv_trailing_metadata_ready_channelz(void* arg,
+                                                  grpc_error* error) {
+  grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
+  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  if (grpc_client_channel_trace.enabled()) {
+    gpr_log(GPR_INFO,
+            "chand=%p calld=%p: got recv_trailing_metadata_ready_channelz, "
+            "error=%s",
+            chand, calld, grpc_error_string(error));
+  }
+  GPR_ASSERT(calld->recv_trailing_metadata != nullptr);
+  grpc_status_code status = GRPC_STATUS_OK;
+  grpc_metadata_batch* md_batch = calld->recv_trailing_metadata;
+  get_call_status(elem, md_batch, GRPC_ERROR_REF(error), &status, nullptr);
+  grpc_core::channelz::SubchannelNode* channelz_subchannel =
+      calld->pick.connected_subchannel->channelz_subchannel();
+  GPR_ASSERT(channelz_subchannel != nullptr);
+  if (status == GRPC_STATUS_OK) {
+    channelz_subchannel->RecordCallSucceeded();
+  } else {
+    channelz_subchannel->RecordCallFailed();
+  }
+  calld->recv_trailing_metadata = nullptr;
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata, error);
+}
+
+// If channelz is enabled, intercept recv_trailing so that we may check the
+// status and associate it to a subchannel.
+// Returns true if callback was intercepted, false otherwise.
+static void maybe_intercept_recv_trailing_metadata_for_channelz(
+    grpc_call_element* elem, grpc_transport_stream_op_batch* batch) {
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  // only intercept payloads with recv trailing.
+  if (!batch->recv_trailing_metadata) {
+    return;
+  }
+  // only add interceptor is channelz is enabled.
+  if (calld->pick.connected_subchannel->channelz_subchannel() == nullptr) {
+    return;
+  }
+  if (grpc_client_channel_trace.enabled()) {
+    gpr_log(GPR_INFO,
+            "calld=%p batch=%p: intercepting recv trailing for channelz", calld,
+            batch);
+  }
+  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready_channelz,
+                    recv_trailing_metadata_ready_channelz, elem,
+                    grpc_schedule_on_exec_ctx);
+  // save some state needed for the interception callback.
+  GPR_ASSERT(calld->recv_trailing_metadata == nullptr);
+  calld->recv_trailing_metadata =
+      batch->payload->recv_trailing_metadata.recv_trailing_metadata;
+  calld->original_recv_trailing_metadata =
+      batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+  batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+      &calld->recv_trailing_metadata_ready_channelz;
+}
+
 //
 // LB pick
 //

src/core/ext/filters/client_channel/parse_address.cc

@@ -125,9 +125,16 @@ bool grpc_parse_ipv6_hostport(const char* hostport, grpc_resolved_address* addr,
   char* host_end = static_cast<char*>(gpr_memrchr(host, '%', strlen(host)));
   if (host_end != nullptr) {
     GPR_ASSERT(host_end >= host);
-    char host_without_scope[GRPC_INET6_ADDRSTRLEN];
+    char host_without_scope[GRPC_INET6_ADDRSTRLEN + 1];
     size_t host_without_scope_len = static_cast<size_t>(host_end - host);
     uint32_t sin6_scope_id = 0;
+    if (host_without_scope_len > GRPC_INET6_ADDRSTRLEN) {
+      gpr_log(GPR_ERROR,
+              "invalid ipv6 address length %zu. Length cannot be greater than "
+              "GRPC_INET6_ADDRSTRLEN i.e %d)",
+              host_without_scope_len, GRPC_INET6_ADDRSTRLEN);
+      goto done;
+    }
     strncpy(host_without_scope, host, host_without_scope_len);
     host_without_scope[host_without_scope_len] = '\0';
     if (grpc_inet_pton(GRPC_AF_INET6, host_without_scope, &in6->sin6_addr) ==

src/core/ext/filters/client_channel/subchannel_index.cc

@@ -42,7 +42,7 @@ struct grpc_subchannel_key {
   grpc_subchannel_args args;
 };
 
-static bool g_force_creation = false;
+static gpr_atm g_force_creation = false;
 
 static grpc_subchannel_key* create_key(
     const grpc_subchannel_args* args,
@@ -73,7 +73,8 @@ static grpc_subchannel_key* subchannel_key_copy(grpc_subchannel_key* k) {
 
 int grpc_subchannel_key_compare(const grpc_subchannel_key* a,
                                 const grpc_subchannel_key* b) {
-  if (g_force_creation) return false;
+  // To pretend the keys are different, return a non-zero value.
+  if (GPR_UNLIKELY(gpr_atm_no_barrier_load(&g_force_creation))) return 1;
   int c = GPR_ICMP(a->args.filter_count, b->args.filter_count);
   if (c != 0) return c;
   if (a->args.filter_count > 0) {
@@ -250,5 +251,5 @@ void grpc_subchannel_index_unregister(grpc_subchannel_key* key,
 }
 
 void grpc_subchannel_index_test_only_set_force_creation(bool force_creation) {
-  g_force_creation = force_creation;
+  gpr_atm_no_barrier_store(&g_force_creation, force_creation);
 }

src/core/ext/filters/client_channel/subchannel_index.h

@@ -65,13 +65,10 @@ void grpc_subchannel_index_ref(void);
 void grpc_subchannel_index_unref(void);
 
 /** \em TEST ONLY.
- * If \a force_creation is true, all key comparisons will be false, resulting in
+ * If \a force_creation is true, all keys are regarded different, resulting in
  * new subchannels always being created. Otherwise, the keys will be compared as
  * usual.
  *
- * This function is *not* threadsafe on purpose: it should *only* be used in
- * test code.
- *
  * Tests using this function \em MUST run tests with and without \a
  * force_creation set. */
 void grpc_subchannel_index_test_only_set_force_creation(bool force_creation);

src/core/ext/filters/http/client/http_client_filter.cc

@@ -51,6 +51,7 @@ struct call_data {
   grpc_linked_mdelem user_agent;
   // State for handling recv_initial_metadata ops.
   grpc_metadata_batch* recv_initial_metadata;
+  grpc_error* recv_initial_metadata_error;
   grpc_closure* original_recv_initial_metadata_ready;
   grpc_closure recv_initial_metadata_ready;
   // State for handling recv_trailing_metadata ops.
@@ -78,7 +79,12 @@ struct channel_data {
 static grpc_error* client_filter_incoming_metadata(grpc_call_element* elem,
                                                    grpc_metadata_batch* b) {
   if (b->idx.named.status != nullptr) {
-    if (grpc_mdelem_eq(b->idx.named.status->md, GRPC_MDELEM_STATUS_200)) {
+    /* If both gRPC status and HTTP status are provided in the response, we
+     * should prefer the gRPC status code, as mentioned in
+     * https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md.
+     */
+    if (b->idx.named.grpc_status != nullptr ||
+        grpc_mdelem_eq(b->idx.named.status->md, GRPC_MDELEM_STATUS_200)) {
       grpc_metadata_batch_remove(b, b->idx.named.status);
     } else {
       char* val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.status->md),
@@ -147,6 +153,7 @@ static void recv_initial_metadata_ready(void* user_data, grpc_error* error) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
   if (error == GRPC_ERROR_NONE) {
     error = client_filter_incoming_metadata(elem, calld->recv_initial_metadata);
+    calld->recv_initial_metadata_error = GRPC_ERROR_REF(error);
   } else {
     GRPC_ERROR_REF(error);
   }
@@ -162,6 +169,8 @@ static void recv_trailing_metadata_ready(void* user_data, grpc_error* error) {
   } else {
     GRPC_ERROR_REF(error);
   }
+  error = grpc_error_add_child(
+      error, GRPC_ERROR_REF(calld->recv_initial_metadata_error));
   GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, error);
 }
 
@@ -434,7 +443,10 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
 /* Destructor for call_data */
 static void destroy_call_elem(grpc_call_element* elem,
                               const grpc_call_final_info* final_info,
-                              grpc_closure* ignored) {}
+                              grpc_closure* ignored) {
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  GRPC_ERROR_UNREF(calld->recv_initial_metadata_error);
+}
 
 static grpc_mdelem scheme_from_args(const grpc_channel_args* args) {
   unsigned i;

src/core/ext/filters/http/server/http_server_filter.cc

@@ -23,6 +23,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <string.h>
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gprpp/manual_constructor.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/b64.h"
@@ -50,6 +51,7 @@ struct call_data {
 
   // State for intercepting recv_initial_metadata.
   grpc_closure recv_initial_metadata_ready;
+  grpc_error* recv_initial_metadata_ready_error;
   grpc_closure* original_recv_initial_metadata_ready;
   grpc_metadata_batch* recv_initial_metadata;
   uint32_t* recv_initial_metadata_flags;
@@ -60,6 +62,13 @@ struct call_data {
   grpc_closure recv_message_ready;
   grpc_core::OrphanablePtr<grpc_core::ByteStream>* recv_message;
   bool seen_recv_message_ready;
+
+  grpc_closure recv_trailing_metadata_ready;
+  grpc_closure* original_recv_trailing_metadata_ready;
+};
+
+struct channel_data {
+  bool surface_user_agent;
 };
 
 }  // namespace
@@ -258,6 +267,11 @@ static grpc_error* hs_filter_incoming_metadata(grpc_call_element* elem,
             GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":authority")));
   }
 
+  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+  if (!chand->surface_user_agent && b->idx.named.user_agent != nullptr) {
+    grpc_metadata_batch_remove(b, b->idx.named.user_agent);
+  }
+
   return error;
 }
 
@@ -267,6 +281,7 @@ static void hs_recv_initial_metadata_ready(void* user_data, grpc_error* err) {
   calld->seen_recv_initial_metadata_ready = true;
   if (err == GRPC_ERROR_NONE) {
     err = hs_filter_incoming_metadata(elem, calld->recv_initial_metadata);
+    calld->recv_initial_metadata_ready_error = GRPC_ERROR_REF(err);
     if (calld->seen_recv_message_ready) {
       // We've already seen the recv_message callback, but we previously
       // deferred it, so we need to return it here.
@@ -313,6 +328,15 @@ static void hs_recv_message_ready(void* user_data, grpc_error* err) {
   }
 }
 
+static void hs_recv_trailing_metadata_ready(void* user_data, grpc_error* err) {
+  grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  err = grpc_error_add_child(
+      GRPC_ERROR_REF(err),
+      GRPC_ERROR_REF(calld->recv_initial_metadata_ready_error));
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, err);
+}
+
 static grpc_error* hs_mutate_op(grpc_call_element* elem,
                                 grpc_transport_stream_op_batch* op) {
   /* grab pointers to our data from the call element */
@@ -357,6 +381,13 @@ static grpc_error* hs_mutate_op(grpc_call_element* elem,
     op->payload->recv_message.recv_message_ready = &calld->recv_message_ready;
   }
 
+  if (op->recv_trailing_metadata) {
+    calld->original_recv_trailing_metadata_ready =
+        op->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+    op->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+        &calld->recv_trailing_metadata_ready;
+  }
+
   if (op->send_trailing_metadata) {
     grpc_error* error = hs_filter_outgoing_metadata(
         elem, op->payload->send_trailing_metadata.send_trailing_metadata);
@@ -389,6 +420,9 @@ static grpc_error* hs_init_call_elem(grpc_call_element* elem,
                     grpc_schedule_on_exec_ctx);
   GRPC_CLOSURE_INIT(&calld->recv_message_ready, hs_recv_message_ready, elem,
                     grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready,
+                    hs_recv_trailing_metadata_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
 
@@ -397,6 +431,7 @@ static void hs_destroy_call_elem(grpc_call_element* elem,
                                  const grpc_call_final_info* final_info,
                                  grpc_closure* ignored) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
+  GRPC_ERROR_UNREF(calld->recv_initial_metadata_ready_error);
   if (calld->have_read_stream) {
     calld->read_stream->Orphan();
   }
@@ -405,7 +440,12 @@ static void hs_destroy_call_elem(grpc_call_element* elem,
 /* Constructor for channel_data */
 static grpc_error* hs_init_channel_elem(grpc_channel_element* elem,
                                         grpc_channel_element_args* args) {
+  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
   GPR_ASSERT(!args->is_last);
+  chand->surface_user_agent = grpc_channel_arg_get_bool(
+      grpc_channel_args_find(args->channel_args,
+                             const_cast<char*>(GRPC_ARG_SURFACE_USER_AGENT)),
+      true);
   return GRPC_ERROR_NONE;
 }
 
@@ -419,7 +459,7 @@ const grpc_channel_filter grpc_http_server_filter = {
     hs_init_call_elem,
     grpc_call_stack_ignore_set_pollset_or_pollset_set,
     hs_destroy_call_elem,
-    0,
+    sizeof(channel_data),
     hs_init_channel_elem,
     hs_destroy_channel_elem,
     grpc_channel_next_get_info,

src/core/ext/filters/max_age/max_age_filter.cc

@@ -429,8 +429,7 @@ static grpc_error* init_channel_elem(grpc_channel_element* elem,
                                    ? GRPC_MILLIS_INF_FUTURE
                                    : DEFAULT_MAX_CONNECTION_IDLE_MS;
   chand->idle_state = MAX_IDLE_STATE_INIT;
-  gpr_atm_no_barrier_store(&chand->last_enter_idle_time_millis,
-                           GRPC_MILLIS_INF_PAST);
+  gpr_atm_no_barrier_store(&chand->last_enter_idle_time_millis, GPR_ATM_MIN);
   for (size_t i = 0; i < args->channel_args->num_args; ++i) {
     if (0 == strcmp(args->channel_args->args[i].key,
                     GRPC_ARG_MAX_CONNECTION_AGE_MS)) {

src/core/ext/filters/message_size/message_size_filter.cc

@@ -99,10 +99,15 @@ struct call_data {
   // recv_message_ready up-call on transport_stream_op, and remember to
   // call our next_recv_message_ready member after handling it.
   grpc_closure recv_message_ready;
+  grpc_closure recv_trailing_metadata_ready;
+  // The error caused by a message that is too large, or GRPC_ERROR_NONE
+  grpc_error* error;
   // Used by recv_message_ready.
   grpc_core::OrphanablePtr<grpc_core::ByteStream>* recv_message;
   // Original recv_message_ready callback, invoked after our own.
   grpc_closure* next_recv_message_ready;
+  // Original recv_trailing_metadata callback, invoked after our own.
+  grpc_closure* original_recv_trailing_metadata_ready;
 };
 
 struct channel_data {
@@ -130,12 +135,13 @@ static void recv_message_ready(void* user_data, grpc_error* error) {
     grpc_error* new_error = grpc_error_set_int(
         GRPC_ERROR_CREATE_FROM_COPIED_STRING(message_string),
         GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_RESOURCE_EXHAUSTED);
+    GRPC_ERROR_UNREF(calld->error);
     if (error == GRPC_ERROR_NONE) {
       error = new_error;
     } else {
       error = grpc_error_add_child(error, new_error);
-      GRPC_ERROR_UNREF(new_error);
     }
+    calld->error = GRPC_ERROR_REF(error);
     gpr_free(message_string);
   } else {
     GRPC_ERROR_REF(error);
@@ -144,6 +150,17 @@ static void recv_message_ready(void* user_data, grpc_error* error) {
   GRPC_CLOSURE_RUN(calld->next_recv_message_ready, error);
 }
 
+// Callback invoked on completion of recv_trailing_metadata
+// Notifies the recv_trailing_metadata batch of any message size failures
+static void recv_trailing_metadata_ready(void* user_data, grpc_error* error) {
+  grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  error =
+      grpc_error_add_child(GRPC_ERROR_REF(error), GRPC_ERROR_REF(calld->error));
+  // Invoke the next callback.
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, error);
+}
+
 // Start transport stream op.
 static void start_transport_stream_op_batch(
     grpc_call_element* elem, grpc_transport_stream_op_batch* op) {
@@ -172,6 +189,13 @@ static void start_transport_stream_op_batch(
     calld->recv_message = op->payload->recv_message.recv_message;
     op->payload->recv_message.recv_message_ready = &calld->recv_message_ready;
   }
+  // Inject callback for receiving trailing metadata.
+  if (op->recv_trailing_metadata) {
+    calld->original_recv_trailing_metadata_ready =
+        op->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+    op->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+        &calld->recv_trailing_metadata_ready;
+  }
   // Chain to the next filter.
   grpc_call_next_op(elem, op);
 }
@@ -183,8 +207,13 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
   call_data* calld = static_cast<call_data*>(elem->call_data);
   calld->call_combiner = args->call_combiner;
   calld->next_recv_message_ready = nullptr;
+  calld->original_recv_trailing_metadata_ready = nullptr;
+  calld->error = GRPC_ERROR_NONE;
   GRPC_CLOSURE_INIT(&calld->recv_message_ready, recv_message_ready, elem,
                     grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready,
+                    recv_trailing_metadata_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   // Get max sizes from channel data, then merge in per-method config values.
   // Note: Per-method config is only available on the client, so we
   // apply the max request size to the send limit and the max response
@@ -213,7 +242,10 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
 // Destructor for call_data.
 static void destroy_call_elem(grpc_call_element* elem,
                               const grpc_call_final_info* final_info,
-                              grpc_closure* ignored) {}
+                              grpc_closure* ignored) {
+  call_data* calld = (call_data*)elem->call_data;
+  GRPC_ERROR_UNREF(calld->error);
+}
 
 static int default_size(const grpc_channel_args* args,
                         int without_minimal_stack) {

src/core/ext/transport/chttp2/transport/chttp2_transport.cc

@@ -230,35 +230,165 @@ void grpc_chttp2_ref_transport(grpc_chttp2_transport* t) { gpr_ref(&t->refs); }
 
 static const grpc_transport_vtable* get_vtable(void);
 
-static void init_transport(grpc_chttp2_transport* t,
-                           const grpc_channel_args* channel_args,
-                           grpc_endpoint* ep, bool is_client) {
+/* Returns whether bdp is enabled */
+static bool read_channel_args(grpc_chttp2_transport* t,
+                              const grpc_channel_args* channel_args,
+                              bool is_client) {
+  bool enable_bdp = true;
   size_t i;
   int j;
 
-  GPR_ASSERT(strlen(GRPC_CHTTP2_CLIENT_CONNECT_STRING) ==
-             GRPC_CHTTP2_CLIENT_CONNECT_STRLEN);
-
-  t->base.vtable = get_vtable();
-  t->ep = ep;
-  /* one ref is for destroy */
-  gpr_ref_init(&t->refs, 1);
-  t->combiner = grpc_combiner_create();
-  t->peer_string = grpc_endpoint_get_peer(ep);
-  t->endpoint_reading = 1;
-  t->next_stream_id = is_client ? 1 : 2;
-  t->is_client = is_client;
-  t->deframe_state = is_client ? GRPC_DTS_FH_0 : GRPC_DTS_CLIENT_PREFIX_0;
-  t->is_first_frame = true;
-  grpc_connectivity_state_init(
-      &t->channel_callback.state_tracker, GRPC_CHANNEL_READY,
-      is_client ? "client_transport" : "server_transport");
-
-  grpc_slice_buffer_init(&t->qbuf);
-
-  grpc_slice_buffer_init(&t->outbuf);
-  grpc_chttp2_hpack_compressor_init(&t->hpack_compressor);
+  for (i = 0; i < channel_args->num_args; i++) {
+    if (0 == strcmp(channel_args->args[i].key,
+                    GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER)) {
+      const grpc_integer_options options = {-1, 0, INT_MAX};
+      const int value =
+          grpc_channel_arg_get_integer(&channel_args->args[i], options);
+      if (value >= 0) {
+        if ((t->next_stream_id & 1) != (value & 1)) {
+          gpr_log(GPR_ERROR, "%s: low bit must be %d on %s",
+                  GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER, t->next_stream_id & 1,
+                  is_client ? "client" : "server");
+        } else {
+          t->next_stream_id = static_cast<uint32_t>(value);
+        }
+      }
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER)) {
+      const grpc_integer_options options = {-1, 0, INT_MAX};
+      const int value =
+          grpc_channel_arg_get_integer(&channel_args->args[i], options);
+      if (value >= 0) {
+        grpc_chttp2_hpack_compressor_set_max_usable_size(
+            &t->hpack_compressor, static_cast<uint32_t>(value));
+      }
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA)) {
+      t->ping_policy.max_pings_without_data = grpc_channel_arg_get_integer(
+          &channel_args->args[i],
+          {g_default_max_pings_without_data, 0, INT_MAX});
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_HTTP2_MAX_PING_STRIKES)) {
+      t->ping_policy.max_ping_strikes = grpc_channel_arg_get_integer(
+          &channel_args->args[i], {g_default_max_ping_strikes, 0, INT_MAX});
+    } else if (0 ==
+               strcmp(channel_args->args[i].key,
+                      GRPC_ARG_HTTP2_MIN_SENT_PING_INTERVAL_WITHOUT_DATA_MS)) {
+      t->ping_policy.min_sent_ping_interval_without_data =
+          grpc_channel_arg_get_integer(
+              &channel_args->args[i],
+              grpc_integer_options{
+                  g_default_min_sent_ping_interval_without_data_ms, 0,
+                  INT_MAX});
+    } else if (0 ==
+               strcmp(channel_args->args[i].key,
+                      GRPC_ARG_HTTP2_MIN_RECV_PING_INTERVAL_WITHOUT_DATA_MS)) {
+      t->ping_policy.min_recv_ping_interval_without_data =
+          grpc_channel_arg_get_integer(
+              &channel_args->args[i],
+              grpc_integer_options{
+                  g_default_min_recv_ping_interval_without_data_ms, 0,
+                  INT_MAX});
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE)) {
+      t->write_buffer_size = static_cast<uint32_t>(grpc_channel_arg_get_integer(
+          &channel_args->args[i], {0, 0, MAX_WRITE_BUFFER_SIZE}));
+    } else if (0 ==
+               strcmp(channel_args->args[i].key, GRPC_ARG_HTTP2_BDP_PROBE)) {
+      enable_bdp = grpc_channel_arg_get_bool(&channel_args->args[i], true);
+    } else if (0 ==
+               strcmp(channel_args->args[i].key, GRPC_ARG_KEEPALIVE_TIME_MS)) {
+      const int value = grpc_channel_arg_get_integer(
+          &channel_args->args[i],
+          grpc_integer_options{t->is_client
+                                   ? g_default_client_keepalive_time_ms
+                                   : g_default_server_keepalive_time_ms,
+                               1, INT_MAX});
+      t->keepalive_time = value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_KEEPALIVE_TIMEOUT_MS)) {
+      const int value = grpc_channel_arg_get_integer(
+          &channel_args->args[i],
+          grpc_integer_options{t->is_client
+                                   ? g_default_client_keepalive_timeout_ms
+                                   : g_default_server_keepalive_timeout_ms,
+                               0, INT_MAX});
+      t->keepalive_timeout = value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_KEEPALIVE_PERMIT_WITHOUT_CALLS)) {
+      t->keepalive_permit_without_calls = static_cast<uint32_t>(
+          grpc_channel_arg_get_integer(&channel_args->args[i], {0, 0, 1}));
+    } else if (0 == strcmp(channel_args->args[i].key,
+                           GRPC_ARG_OPTIMIZATION_TARGET)) {
+      if (channel_args->args[i].type != GRPC_ARG_STRING) {
+        gpr_log(GPR_ERROR, "%s should be a string",
+                GRPC_ARG_OPTIMIZATION_TARGET);
+      } else if (0 == strcmp(channel_args->args[i].value.string, "blend")) {
+        t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
+      } else if (0 == strcmp(channel_args->args[i].value.string, "latency")) {
+        t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
+      } else if (0 ==
+                 strcmp(channel_args->args[i].value.string, "throughput")) {
+        t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT;
+      } else {
+        gpr_log(GPR_ERROR, "%s value '%s' unknown, assuming 'blend'",
+                GRPC_ARG_OPTIMIZATION_TARGET,
+                channel_args->args[i].value.string);
+      }
+    } else {
+      static const struct {
+        const char* channel_arg_name;
+        grpc_chttp2_setting_id setting_id;
+        grpc_integer_options integer_options;
+        bool availability[2] /* server, client */;
+      } settings_map[] = {{GRPC_ARG_MAX_CONCURRENT_STREAMS,
+                           GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+                           {-1, 0, INT32_MAX},
+                           {true, false}},
+                          {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
+                           GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
+                           {-1, 0, INT32_MAX},
+                           {true, true}},
+                          {GRPC_ARG_MAX_METADATA_SIZE,
+                           GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+                           {-1, 0, INT32_MAX},
+                           {true, true}},
+                          {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
+                           GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
+                           {-1, 16384, 16777215},
+                           {true, true}},
+                          {GRPC_ARG_HTTP2_ENABLE_TRUE_BINARY,
+                           GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA,
+                           {1, 0, 1},
+                           {true, true}},
+                          {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
+                           GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+                           {-1, 5, INT32_MAX},
+                           {true, true}}};
+      for (j = 0; j < static_cast<int> GPR_ARRAY_SIZE(settings_map); j++) {
+        if (0 == strcmp(channel_args->args[i].key,
+                        settings_map[j].channel_arg_name)) {
+          if (!settings_map[j].availability[is_client]) {
+            gpr_log(GPR_DEBUG, "%s is not available on %s",
+                    settings_map[j].channel_arg_name,
+                    is_client ? "clients" : "servers");
+          } else {
+            int value = grpc_channel_arg_get_integer(
+                &channel_args->args[i], settings_map[j].integer_options);
+            if (value >= 0) {
+              queue_setting_update(t, settings_map[j].setting_id,
+                                   static_cast<uint32_t>(value));
+            }
+          }
+          break;
+        }
+      }
+    }
+  }
+  return enable_bdp;
+}
 
+static void init_transport_closures(grpc_chttp2_transport* t) {
   GRPC_CLOSURE_INIT(&t->read_action_locked, read_action_locked, t,
                     grpc_combiner_scheduler(t->combiner));
   GRPC_CLOSURE_INIT(&t->benign_reclaimer_locked, benign_reclaimer_locked, t,
@@ -286,6 +416,79 @@ static void init_transport(grpc_chttp2_transport* t,
   GRPC_CLOSURE_INIT(&t->keepalive_watchdog_fired_locked,
                     keepalive_watchdog_fired_locked, t,
                     grpc_combiner_scheduler(t->combiner));
+}
+
+static void init_transport_keepalive_settings(grpc_chttp2_transport* t) {
+  if (t->is_client) {
+    t->keepalive_time = g_default_client_keepalive_time_ms == INT_MAX
+                            ? GRPC_MILLIS_INF_FUTURE
+                            : g_default_client_keepalive_time_ms;
+    t->keepalive_timeout = g_default_client_keepalive_timeout_ms == INT_MAX
+                               ? GRPC_MILLIS_INF_FUTURE
+                               : g_default_client_keepalive_timeout_ms;
+    t->keepalive_permit_without_calls =
+        g_default_client_keepalive_permit_without_calls;
+  } else {
+    t->keepalive_time = g_default_server_keepalive_time_ms == INT_MAX
+                            ? GRPC_MILLIS_INF_FUTURE
+                            : g_default_server_keepalive_time_ms;
+    t->keepalive_timeout = g_default_server_keepalive_timeout_ms == INT_MAX
+                               ? GRPC_MILLIS_INF_FUTURE
+                               : g_default_server_keepalive_timeout_ms;
+    t->keepalive_permit_without_calls =
+        g_default_server_keepalive_permit_without_calls;
+  }
+}
+
+static void configure_transport_ping_policy(grpc_chttp2_transport* t) {
+  t->ping_policy.max_pings_without_data = g_default_max_pings_without_data;
+  t->ping_policy.min_sent_ping_interval_without_data =
+      g_default_min_sent_ping_interval_without_data_ms;
+  t->ping_policy.max_ping_strikes = g_default_max_ping_strikes;
+  t->ping_policy.min_recv_ping_interval_without_data =
+      g_default_min_recv_ping_interval_without_data_ms;
+}
+
+static void init_keepalive_pings_if_enabled(grpc_chttp2_transport* t) {
+  if (t->keepalive_time != GRPC_MILLIS_INF_FUTURE) {
+    t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_WAITING;
+    GRPC_CHTTP2_REF_TRANSPORT(t, "init keepalive ping");
+    grpc_timer_init(&t->keepalive_ping_timer,
+                    grpc_core::ExecCtx::Get()->Now() + t->keepalive_time,
+                    &t->init_keepalive_ping_locked);
+  } else {
+    /* Use GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED to indicate there are no
+       inflight keeaplive timers */
+    t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED;
+  }
+}
+
+static void init_transport(grpc_chttp2_transport* t,
+                           const grpc_channel_args* channel_args,
+                           grpc_endpoint* ep, bool is_client) {
+  GPR_ASSERT(strlen(GRPC_CHTTP2_CLIENT_CONNECT_STRING) ==
+             GRPC_CHTTP2_CLIENT_CONNECT_STRLEN);
+
+  t->base.vtable = get_vtable();
+  t->ep = ep;
+  /* one ref is for destroy */
+  gpr_ref_init(&t->refs, 1);
+  t->combiner = grpc_combiner_create();
+  t->peer_string = grpc_endpoint_get_peer(ep);
+  t->endpoint_reading = 1;
+  t->next_stream_id = is_client ? 1 : 2;
+  t->is_client = is_client;
+  t->deframe_state = is_client ? GRPC_DTS_FH_0 : GRPC_DTS_CLIENT_PREFIX_0;
+  t->is_first_frame = true;
+  grpc_connectivity_state_init(
+      &t->channel_callback.state_tracker, GRPC_CHANNEL_READY,
+      is_client ? "client_transport" : "server_transport");
+
+  grpc_slice_buffer_init(&t->qbuf);
+  grpc_slice_buffer_init(&t->outbuf);
+  grpc_chttp2_hpack_compressor_init(&t->hpack_compressor);
+
+  init_transport_closures(t);
 
   t->goaway_error = GRPC_ERROR_NONE;
   grpc_chttp2_goaway_parser_init(&t->goaway_parser);
@@ -301,6 +504,8 @@ static void init_transport(grpc_chttp2_transport* t,
   grpc_chttp2_stream_map_init(&t->stream_map, 8);
 
   /* copy in initial settings to all setting sets */
+  size_t i;
+  int j;
   for (i = 0; i < GRPC_CHTTP2_NUM_SETTINGS; i++) {
     for (j = 0; j < GRPC_NUM_SETTING_SETS; j++) {
       t->settings[j][i] = grpc_chttp2_settings_parameters[i].default_value;
@@ -328,191 +533,14 @@ static void init_transport(grpc_chttp2_transport* t,
   queue_setting_update(t, GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA,
                        1);
 
-  t->ping_policy.max_pings_without_data = g_default_max_pings_without_data;
-  t->ping_policy.min_sent_ping_interval_without_data =
-      g_default_min_sent_ping_interval_without_data_ms;
-  t->ping_policy.max_ping_strikes = g_default_max_ping_strikes;
-  t->ping_policy.min_recv_ping_interval_without_data =
-      g_default_min_recv_ping_interval_without_data_ms;
-
-  /* Keepalive setting */
-  if (t->is_client) {
-    t->keepalive_time = g_default_client_keepalive_time_ms == INT_MAX
-                            ? GRPC_MILLIS_INF_FUTURE
-                            : g_default_client_keepalive_time_ms;
-    t->keepalive_timeout = g_default_client_keepalive_timeout_ms == INT_MAX
-                               ? GRPC_MILLIS_INF_FUTURE
-                               : g_default_client_keepalive_timeout_ms;
-    t->keepalive_permit_without_calls =
-        g_default_client_keepalive_permit_without_calls;
-  } else {
-    t->keepalive_time = g_default_server_keepalive_time_ms == INT_MAX
-                            ? GRPC_MILLIS_INF_FUTURE
-                            : g_default_server_keepalive_time_ms;
-    t->keepalive_timeout = g_default_server_keepalive_timeout_ms == INT_MAX
-                               ? GRPC_MILLIS_INF_FUTURE
-                               : g_default_server_keepalive_timeout_ms;
-    t->keepalive_permit_without_calls =
-        g_default_server_keepalive_permit_without_calls;
-  }
+  configure_transport_ping_policy(t);
+  init_transport_keepalive_settings(t);
 
   t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
 
   bool enable_bdp = true;
-
   if (channel_args) {
-    for (i = 0; i < channel_args->num_args; i++) {
-      if (0 == strcmp(channel_args->args[i].key,
-                      GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER)) {
-        const grpc_integer_options options = {-1, 0, INT_MAX};
-        const int value =
-            grpc_channel_arg_get_integer(&channel_args->args[i], options);
-        if (value >= 0) {
-          if ((t->next_stream_id & 1) != (value & 1)) {
-            gpr_log(GPR_ERROR, "%s: low bit must be %d on %s",
-                    GRPC_ARG_HTTP2_INITIAL_SEQUENCE_NUMBER,
-                    t->next_stream_id & 1, is_client ? "client" : "server");
-          } else {
-            t->next_stream_id = static_cast<uint32_t>(value);
-          }
-        }
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER)) {
-        const grpc_integer_options options = {-1, 0, INT_MAX};
-        const int value =
-            grpc_channel_arg_get_integer(&channel_args->args[i], options);
-        if (value >= 0) {
-          grpc_chttp2_hpack_compressor_set_max_usable_size(
-              &t->hpack_compressor, static_cast<uint32_t>(value));
-        }
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA)) {
-        t->ping_policy.max_pings_without_data = grpc_channel_arg_get_integer(
-            &channel_args->args[i],
-            {g_default_max_pings_without_data, 0, INT_MAX});
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_MAX_PING_STRIKES)) {
-        t->ping_policy.max_ping_strikes = grpc_channel_arg_get_integer(
-            &channel_args->args[i], {g_default_max_ping_strikes, 0, INT_MAX});
-      } else if (0 ==
-                 strcmp(
-                     channel_args->args[i].key,
-                     GRPC_ARG_HTTP2_MIN_SENT_PING_INTERVAL_WITHOUT_DATA_MS)) {
-        t->ping_policy.min_sent_ping_interval_without_data =
-            grpc_channel_arg_get_integer(
-                &channel_args->args[i],
-                grpc_integer_options{
-                    g_default_min_sent_ping_interval_without_data_ms, 0,
-                    INT_MAX});
-      } else if (0 ==
-                 strcmp(
-                     channel_args->args[i].key,
-                     GRPC_ARG_HTTP2_MIN_RECV_PING_INTERVAL_WITHOUT_DATA_MS)) {
-        t->ping_policy.min_recv_ping_interval_without_data =
-            grpc_channel_arg_get_integer(
-                &channel_args->args[i],
-                grpc_integer_options{
-                    g_default_min_recv_ping_interval_without_data_ms, 0,
-                    INT_MAX});
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE)) {
-        t->write_buffer_size =
-            static_cast<uint32_t>(grpc_channel_arg_get_integer(
-                &channel_args->args[i], {0, 0, MAX_WRITE_BUFFER_SIZE}));
-      } else if (0 ==
-                 strcmp(channel_args->args[i].key, GRPC_ARG_HTTP2_BDP_PROBE)) {
-        enable_bdp = grpc_channel_arg_get_bool(&channel_args->args[i], true);
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_KEEPALIVE_TIME_MS)) {
-        const int value = grpc_channel_arg_get_integer(
-            &channel_args->args[i],
-            grpc_integer_options{t->is_client
-                                     ? g_default_client_keepalive_time_ms
-                                     : g_default_server_keepalive_time_ms,
-                                 1, INT_MAX});
-        t->keepalive_time = value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_KEEPALIVE_TIMEOUT_MS)) {
-        const int value = grpc_channel_arg_get_integer(
-            &channel_args->args[i],
-            grpc_integer_options{t->is_client
-                                     ? g_default_client_keepalive_timeout_ms
-                                     : g_default_server_keepalive_timeout_ms,
-                                 0, INT_MAX});
-        t->keepalive_timeout =
-            value == INT_MAX ? GRPC_MILLIS_INF_FUTURE : value;
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_KEEPALIVE_PERMIT_WITHOUT_CALLS)) {
-        t->keepalive_permit_without_calls = static_cast<uint32_t>(
-            grpc_channel_arg_get_integer(&channel_args->args[i], {0, 0, 1}));
-      } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_OPTIMIZATION_TARGET)) {
-        if (channel_args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s should be a string",
-                  GRPC_ARG_OPTIMIZATION_TARGET);
-        } else if (0 == strcmp(channel_args->args[i].value.string, "blend")) {
-          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
-        } else if (0 == strcmp(channel_args->args[i].value.string, "latency")) {
-          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_LATENCY;
-        } else if (0 ==
-                   strcmp(channel_args->args[i].value.string, "throughput")) {
-          t->opt_target = GRPC_CHTTP2_OPTIMIZE_FOR_THROUGHPUT;
-        } else {
-          gpr_log(GPR_ERROR, "%s value '%s' unknown, assuming 'blend'",
-                  GRPC_ARG_OPTIMIZATION_TARGET,
-                  channel_args->args[i].value.string);
-        }
-      } else {
-        static const struct {
-          const char* channel_arg_name;
-          grpc_chttp2_setting_id setting_id;
-          grpc_integer_options integer_options;
-          bool availability[2] /* server, client */;
-        } settings_map[] = {
-            {GRPC_ARG_MAX_CONCURRENT_STREAMS,
-             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
-             {-1, 0, INT32_MAX},
-             {true, false}},
-            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
-             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
-             {-1, 0, INT32_MAX},
-             {true, true}},
-            {GRPC_ARG_MAX_METADATA_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-             {-1, 0, INT32_MAX},
-             {true, true}},
-            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
-             {-1, 16384, 16777215},
-             {true, true}},
-            {GRPC_ARG_HTTP2_ENABLE_TRUE_BINARY,
-             GRPC_CHTTP2_SETTINGS_GRPC_ALLOW_TRUE_BINARY_METADATA,
-             {1, 0, 1},
-             {true, true}},
-            {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
-             GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
-             {-1, 5, INT32_MAX},
-             {true, true}}};
-        for (j = 0; j < static_cast<int> GPR_ARRAY_SIZE(settings_map); j++) {
-          if (0 == strcmp(channel_args->args[i].key,
-                          settings_map[j].channel_arg_name)) {
-            if (!settings_map[j].availability[is_client]) {
-              gpr_log(GPR_DEBUG, "%s is not available on %s",
-                      settings_map[j].channel_arg_name,
-                      is_client ? "clients" : "servers");
-            } else {
-              int value = grpc_channel_arg_get_integer(
-                  &channel_args->args[i], settings_map[j].integer_options);
-              if (value >= 0) {
-                queue_setting_update(t, settings_map[j].setting_id,
-                                     static_cast<uint32_t>(value));
-              }
-            }
-            break;
-          }
-        }
-      }
-    }
+    enable_bdp = read_channel_args(t, channel_args, is_client);
   }
 
   if (g_flow_control_enabled) {
@@ -531,23 +559,11 @@ static void init_transport(grpc_chttp2_transport* t,
   t->ping_recv_state.last_ping_recv_time = GRPC_MILLIS_INF_PAST;
   t->ping_recv_state.ping_strikes = 0;
 
-  /* Start keepalive pings */
-  if (t->keepalive_time != GRPC_MILLIS_INF_FUTURE) {
-    t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_WAITING;
-    GRPC_CHTTP2_REF_TRANSPORT(t, "init keepalive ping");
-    grpc_timer_init(&t->keepalive_ping_timer,
-                    grpc_core::ExecCtx::Get()->Now() + t->keepalive_time,
-                    &t->init_keepalive_ping_locked);
-  } else {
-    /* Use GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED to indicate there are no
-       inflight keeaplive timers */
-    t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED;
-  }
+  init_keepalive_pings_if_enabled(t);
 
   if (enable_bdp) {
     GRPC_CHTTP2_REF_TRANSPORT(t, "bdp_ping");
     schedule_bdp_ping_locked(t);
-
     grpc_chttp2_act_on_flowctl_action(t->flow_control->PeriodicUpdate(), t,
                                       nullptr);
   }
@@ -2887,17 +2903,20 @@ bool Chttp2IncomingByteStream::Next(size_t max_size_hint,
   }
 }
 
+void Chttp2IncomingByteStream::MaybeCreateStreamDecompressionCtx() {
+  if (!stream_->stream_decompression_ctx) {
+    stream_->stream_decompression_ctx = grpc_stream_compression_context_create(
+        stream_->stream_decompression_method);
+  }
+}
+
 grpc_error* Chttp2IncomingByteStream::Pull(grpc_slice* slice) {
   GPR_TIMER_SCOPE("incoming_byte_stream_pull", 0);
   grpc_error* error;
   if (stream_->unprocessed_incoming_frames_buffer.length > 0) {
     if (!stream_->unprocessed_incoming_frames_decompressed) {
       bool end_of_context;
-      if (!stream_->stream_decompression_ctx) {
-        stream_->stream_decompression_ctx =
-            grpc_stream_compression_context_create(
-                stream_->stream_decompression_method);
-      }
+      MaybeCreateStreamDecompressionCtx();
       if (!grpc_stream_decompress(stream_->stream_decompression_ctx,
                                   &stream_->unprocessed_incoming_frames_buffer,
                                   &stream_->decompressed_data_buffer, nullptr,

src/core/ext/transport/chttp2/transport/internal.h

@@ -246,6 +246,8 @@ class Chttp2IncomingByteStream : public ByteStream {
   static void NextLocked(void* arg, grpc_error* error_ignored);
   static void OrphanLocked(void* arg, grpc_error* error_ignored);
 
+  void MaybeCreateStreamDecompressionCtx();
+
   grpc_chttp2_transport* transport_;  // Immutable.
   grpc_chttp2_stream* stream_;        // Immutable.
 

src/core/ext/transport/cronet/transport/cronet_transport.cc

@@ -1287,7 +1287,7 @@ static enum e_op_result execute_stream_op(struct op_and_state* oas) {
     grpc_error* error = GRPC_ERROR_NONE;
     if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
       error = GRPC_ERROR_REF(stream_state->cancel_error);
-    } else if (stream_state->state_op_done[OP_FAILED]) {
+    } else if (stream_state->state_callback_received[OP_FAILED]) {
       error = make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable.");
     } else if (oas->s->state.rs.trailing_metadata_valid) {
       grpc_chttp2_incoming_metadata_buffer_publish(

src/core/lib/channel/channelz.cc

@@ -181,9 +181,6 @@ grpc_json* ServerNode::RenderJson() {
   // ask CallCountingHelper to populate trace and call count data.
   call_counter_.PopulateCallCounts(json);
   json = top_level_json;
-  // template method. Child classes may override this to add their specific
-  // functionality.
-  PopulateSockets(json);
   return top_level_json;
 }
 

src/core/lib/channel/channelz.h

@@ -79,7 +79,7 @@ class BaseNode : public RefCounted<BaseNode> {
   const intptr_t uuid_;
 };
 
-// This class is a helper class for channelz entities that deal with Channels
+// This class is a helper class for channelz entities that deal with Channels,
 // Subchannels, and Servers, since those have similar proto definitions.
 // This class has the ability to:
 //   - track calls_{started,succeeded,failed}
@@ -133,6 +133,9 @@ class ChannelNode : public BaseNode {
   // so it leaves these implementations blank.
   //
   // This is utilizing the template method design pattern.
+  //
+  // TODO(ncteisen): remove these template methods in favor of manual traversal
+  // and mutation of the grpc_json object.
   virtual void PopulateConnectivityState(grpc_json* json) {}
   virtual void PopulateChildRefs(grpc_json* json) {}
 
@@ -158,7 +161,7 @@ class ChannelNode : public BaseNode {
   void RecordCallSucceeded() { call_counter_.RecordCallSucceeded(); }
 
  private:
-  // to allow the channel trace test to access trace();
+  // to allow the channel trace test to access trace_.
   friend class testing::ChannelNodePeer;
   grpc_channel* channel_ = nullptr;
   UniquePtr<char> target_;
@@ -174,8 +177,6 @@ class ServerNode : public BaseNode {
 
   grpc_json* RenderJson() override;
 
-  void PopulateSockets(grpc_json* json) {}
-
   // proxy methods to composed classes.
   void AddTraceEvent(ChannelTrace::Severity severity, grpc_slice data) {
     trace_.AddTraceEvent(severity, data);

src/core/lib/channel/connected_channel.cc

@@ -104,18 +104,18 @@ static void con_start_transport_stream_op_batch(
   if (batch->recv_initial_metadata) {
     callback_state* state = &calld->recv_initial_metadata_ready;
     intercept_callback(
-        calld, state, false, "connected_recv_initial_metadata_ready",
+        calld, state, false, "recv_initial_metadata_ready",
         &batch->payload->recv_initial_metadata.recv_initial_metadata_ready);
   }
   if (batch->recv_message) {
     callback_state* state = &calld->recv_message_ready;
-    intercept_callback(calld, state, false, "connected_recv_message_ready",
+    intercept_callback(calld, state, false, "recv_message_ready",
                        &batch->payload->recv_message.recv_message_ready);
   }
   if (batch->recv_trailing_metadata) {
     callback_state* state = &calld->recv_trailing_metadata_ready;
     intercept_callback(
-        calld, state, false, "connected_recv_trailing_metadata_ready",
+        calld, state, false, "recv_trailing_metadata_ready",
         &batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready);
   }
   if (batch->cancel_stream) {
@@ -126,13 +126,11 @@ static void con_start_transport_stream_op_batch(
     // closure for each one.
     callback_state* state =
         static_cast<callback_state*>(gpr_malloc(sizeof(*state)));
-    intercept_callback(calld, state, true,
-                       "connected_on_complete (cancel_stream)",
+    intercept_callback(calld, state, true, "on_complete (cancel_stream)",
                        &batch->on_complete);
   } else if (batch->on_complete != nullptr) {
     callback_state* state = get_state_for_batch(calld, batch);
-    intercept_callback(calld, state, false, "connected_on_complete",
-                       &batch->on_complete);
+    intercept_callback(calld, state, false, "on_complete", &batch->on_complete);
   }
   grpc_transport_perform_stream_op(
       chand->transport, TRANSPORT_STREAM_FROM_CALL_DATA(calld), batch);

src/core/lib/iomgr/error.cc

@@ -513,9 +513,24 @@ bool grpc_error_get_str(grpc_error* err, grpc_error_strs which,
 
 grpc_error* grpc_error_add_child(grpc_error* src, grpc_error* child) {
   GPR_TIMER_SCOPE("grpc_error_add_child", 0);
-  grpc_error* new_err = copy_error_and_unref(src);
-  internal_add_error(&new_err, child);
-  return new_err;
+  if (src != GRPC_ERROR_NONE) {
+    if (child == GRPC_ERROR_NONE) {
+      /* \a child is empty. Simply return the ref to \a src */
+      return src;
+    } else if (child != src) {
+      grpc_error* new_err = copy_error_and_unref(src);
+      internal_add_error(&new_err, child);
+      return new_err;
+    } else {
+      /* \a src and \a child are the same. Drop one of the references and return
+       * the other */
+      GRPC_ERROR_UNREF(child);
+      return src;
+    }
+  } else {
+    /* \a src is empty. Simply return the ref to \a child */
+    return child;
+  }
 }
 
 static const char* no_error_string = "\"No Error\"";

src/core/lib/iomgr/error.h

@@ -185,8 +185,16 @@ bool grpc_error_get_str(grpc_error* error, grpc_error_strs which,
 /// error occurring. Allows root causing high level errors from lower level
 /// errors that contributed to them. The src error takes ownership of the
 /// child error.
+///
+/// Edge Conditions -
+/// 1) If either of \a src or \a child is GRPC_ERROR_NONE, returns a reference
+/// to the other argument. 2) If both \a src and \a child are GRPC_ERROR_NONE,
+/// returns GRPC_ERROR_NONE. 3) If \a src and \a child point to the same error,
+/// returns a single reference. (Note that, 2 references should have been
+/// received to the error in this case.)
 grpc_error* grpc_error_add_child(grpc_error* src,
                                  grpc_error* child) GRPC_MUST_USE_RESULT;
+
 grpc_error* grpc_os_error(const char* file, int line, int err,
                           const char* call_name) GRPC_MUST_USE_RESULT;
 

src/core/lib/iomgr/timer_generic.cc

@@ -291,7 +291,7 @@ static void timer_list_init() {
 static void timer_list_shutdown() {
   size_t i;
   run_some_expired_timers(
-      GPR_ATM_MAX, nullptr,
+      GRPC_MILLIS_INF_FUTURE, nullptr,
       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Timer list shutdown"));
   for (i = 0; i < g_num_shards; i++) {
     timer_shard* shard = &g_shards[i];
@@ -714,9 +714,10 @@ static grpc_timer_check_result timer_check(grpc_millis* next) {
 #if GPR_ARCH_64
     gpr_log(GPR_INFO,
             "TIMER CHECK BEGIN: now=%" PRId64 " next=%s tls_min=%" PRId64
-            " glob_min=%" PRIdPTR,
+            " glob_min=%" PRId64,
             now, next_str, min_timer,
-            gpr_atm_no_barrier_load((gpr_atm*)(&g_shared_mutables.min_timer)));
+            static_cast<grpc_millis>(gpr_atm_no_barrier_load(
+                (gpr_atm*)(&g_shared_mutables.min_timer))));
 #else
     gpr_log(GPR_INFO, "TIMER CHECK BEGIN: now=%" PRId64 " next=%s min=%" PRId64,
             now, next_str, min_timer);

src/core/lib/security/security_connector/security_connector.cc

@@ -59,8 +59,8 @@ static const char* installed_roots_path =
 
 /** Environment variable used as a flag to enable/disable loading system root
     certificates from the OS trust store. */
-#ifndef GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR
-#define GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR "GRPC_USE_SYSTEM_SSL_ROOTS"
+#ifndef GRPC_NOT_USE_SYSTEM_SSL_ROOTS_ENV_VAR
+#define GRPC_NOT_USE_SYSTEM_SSL_ROOTS_ENV_VAR "GRPC_NOT_USE_SYSTEM_SSL_ROOTS"
 #endif
 
 #ifndef TSI_OPENSSL_ALPN_SUPPORT
@@ -1192,10 +1192,10 @@ const char* DefaultSslRootStore::GetPemRootCerts() {
 
 grpc_slice DefaultSslRootStore::ComputePemRootCerts() {
   grpc_slice result = grpc_empty_slice();
-  char* use_system_roots_env_value =
-      gpr_getenv(GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR);
-  const bool use_system_roots = gpr_is_true(use_system_roots_env_value);
-  gpr_free(use_system_roots_env_value);
+  char* not_use_system_roots_env_value =
+      gpr_getenv(GRPC_NOT_USE_SYSTEM_SSL_ROOTS_ENV_VAR);
+  const bool not_use_system_roots = gpr_is_true(not_use_system_roots_env_value);
+  gpr_free(not_use_system_roots_env_value);
   // First try to load the roots from the environment.
   char* default_root_certs_path =
       gpr_getenv(GRPC_DEFAULT_SSL_ROOTS_FILE_PATH_ENV_VAR);
@@ -1218,7 +1218,7 @@ grpc_slice DefaultSslRootStore::ComputePemRootCerts() {
     gpr_free(pem_root_certs);
   }
   // Try loading roots from OS trust store if flag is enabled.
-  if (GRPC_SLICE_IS_EMPTY(result) && use_system_roots) {
+  if (GRPC_SLICE_IS_EMPTY(result) && !not_use_system_roots) {
     result = LoadSystemRootCerts();
   }
   // Fallback to roots manually shipped with gRPC.

src/core/lib/security/transport/server_auth_filter.cc

@@ -41,6 +41,9 @@ struct call_data {
   grpc_transport_stream_op_batch* recv_initial_metadata_batch;
   grpc_closure* original_recv_initial_metadata_ready;
   grpc_closure recv_initial_metadata_ready;
+  grpc_error* error;
+  grpc_closure recv_trailing_metadata_ready;
+  grpc_closure* original_recv_trailing_metadata_ready;
   grpc_metadata_array md;
   const grpc_metadata* consumed_md;
   size_t num_consumed_md;
@@ -111,6 +114,7 @@ static void on_md_processing_done_inner(grpc_call_element* elem,
         batch->payload->recv_initial_metadata.recv_initial_metadata,
         remove_consumed_md, elem, "Response metadata filtering error");
   }
+  calld->error = GRPC_ERROR_REF(error);
   GRPC_CLOSURE_SCHED(calld->original_recv_initial_metadata_ready, error);
 }
 
@@ -184,6 +188,13 @@ static void recv_initial_metadata_ready(void* arg, grpc_error* error) {
                    GRPC_ERROR_REF(error));
 }
 
+static void recv_trailing_metadata_ready(void* user_data, grpc_error* err) {
+  grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  err = grpc_error_add_child(GRPC_ERROR_REF(err), GRPC_ERROR_REF(calld->error));
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, err);
+}
+
 static void auth_start_transport_stream_op_batch(
     grpc_call_element* elem, grpc_transport_stream_op_batch* batch) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
@@ -195,6 +206,12 @@ static void auth_start_transport_stream_op_batch(
     batch->payload->recv_initial_metadata.recv_initial_metadata_ready =
         &calld->recv_initial_metadata_ready;
   }
+  if (batch->recv_trailing_metadata) {
+    calld->original_recv_trailing_metadata_ready =
+        batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+    batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+        &calld->recv_trailing_metadata_ready;
+  }
   grpc_call_next_op(elem, batch);
 }
 
@@ -208,6 +225,9 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
   GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
                     recv_initial_metadata_ready, elem,
                     grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready,
+                    recv_trailing_metadata_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   // Create server security context.  Set its auth context from channel
   // data and save it in the call context.
   grpc_server_security_context* server_ctx =
@@ -227,7 +247,10 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
 /* Destructor for call_data */
 static void destroy_call_elem(grpc_call_element* elem,
                               const grpc_call_final_info* final_info,
-                              grpc_closure* ignored) {}
+                              grpc_closure* ignored) {
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  GRPC_ERROR_UNREF(calld->error);
+}
 
 /* Constructor for channel_data */
 static grpc_error* init_channel_elem(grpc_channel_element* elem,

src/core/lib/surface/call.cc

@@ -72,46 +72,6 @@
 // Used to create arena for the first call.
 #define ESTIMATED_MDELEM_COUNT 16
 
-/* Status data for a request can come from several sources; this
-   enumerates them all, and acts as a priority sorting for which
-   status to return to the application - earlier entries override
-   later ones */
-typedef enum {
-  /* Status came from the application layer overriding whatever
-     the wire says */
-  STATUS_FROM_API_OVERRIDE = 0,
-  /* Status came from 'the wire' - or somewhere below the surface
-     layer */
-  STATUS_FROM_WIRE,
-  /* Status was created by some internal channel stack operation: must come via
-     add_batch_error */
-  STATUS_FROM_CORE,
-  /* Status was created by some surface error */
-  STATUS_FROM_SURFACE,
-  /* Status came from the server sending status */
-  STATUS_FROM_SERVER_STATUS,
-  STATUS_SOURCE_COUNT
-} status_source;
-
-typedef struct {
-  bool is_set;
-  grpc_error* error;
-} received_status;
-
-static gpr_atm pack_received_status(received_status r) {
-  return r.is_set ? (1 | (gpr_atm)r.error) : 0;
-}
-
-static received_status unpack_received_status(gpr_atm atm) {
-  if ((atm & 1) == 0) {
-    return {false, GRPC_ERROR_NONE};
-  } else {
-    return {true, (grpc_error*)(atm & ~static_cast<gpr_atm>(1))};
-  }
-}
-
-#define MAX_ERRORS_PER_BATCH 4
-
 typedef struct batch_control {
   grpc_call* call;
   /* Share memory for cq_completion and notify_tag as they are never needed
@@ -136,10 +96,7 @@ typedef struct batch_control {
   grpc_closure start_batch;
   grpc_closure finish_batch;
   gpr_refcount steps_to_complete;
-
-  grpc_error* errors[MAX_ERRORS_PER_BATCH];
-  gpr_atm num_errors;
-
+  grpc_error* batch_error;
   grpc_transport_stream_op_batch op;
 } batch_control;
 
@@ -167,8 +124,6 @@ struct grpc_call {
   grpc_completion_queue* cq;
   grpc_polling_entity pollent;
   grpc_channel* channel;
-  // backpointer to owning server if this is a server side call.
-  grpc_server* server;
   gpr_timespec start_time;
   /* parent_call* */ gpr_atm parent_call_atm;
   child_call* child;
@@ -204,9 +159,6 @@ struct grpc_call {
   // A char* indicating the peer name.
   gpr_atm peer_string;
 
-  /* Packed received call statuses from various sources */
-  gpr_atm status[STATUS_SOURCE_COUNT];
-
   /* Call data useful used for reporting. Only valid after the call has
    * completed */
   grpc_call_final_info final_info;
@@ -239,6 +191,7 @@ struct grpc_call {
   grpc_closure receiving_initial_metadata_ready;
   grpc_closure receiving_trailing_metadata_ready;
   uint32_t test_only_last_message_flags;
+  gpr_atm cancelled;
 
   grpc_closure release_call;
 
@@ -250,8 +203,11 @@ struct grpc_call {
     } client;
     struct {
       int* cancelled;
+      // backpointer to owning server if this is a server side call.
+      grpc_server* server;
     } server;
   } final_op;
+  grpc_error* status_error;
 
   /* recv_state can contain one of the following values:
      RECV_NONE :                 :  no initial metadata and messages received
@@ -289,23 +245,15 @@ grpc_core::TraceFlag grpc_compression_trace(false, "compression");
 
 static void execute_batch(grpc_call* call, grpc_transport_stream_op_batch* op,
                           grpc_closure* start_batch_closure);
-static void cancel_with_status(grpc_call* c, status_source source,
-                               grpc_status_code status,
+
+static void cancel_with_status(grpc_call* c, grpc_status_code status,
                                const char* description);
-static void cancel_with_error(grpc_call* c, status_source source,
-                              grpc_error* error);
+static void cancel_with_error(grpc_call* c, grpc_error* error);
 static void destroy_call(void* call_stack, grpc_error* error);
 static void receiving_slice_ready(void* bctlp, grpc_error* error);
-static void get_final_status(
-    grpc_call* call, void (*set_value)(grpc_status_code code, void* user_data),
-    void* set_value_user_data, grpc_slice* details, const char** error_string);
-static void set_status_value_directly(grpc_status_code status, void* dest);
-static void set_status_from_error(grpc_call* call, status_source source,
-                                  grpc_error* error);
+static void set_final_status(grpc_call* call, grpc_error* error);
 static void process_data_after_md(batch_control* bctl);
 static void post_batch_completion(batch_control* bctl);
-static void add_batch_error(batch_control* bctl, grpc_error* error,
-                            bool has_cancelled);
 
 static void add_init_error(grpc_error** composite, grpc_error* new_err) {
   if (new_err == GRPC_ERROR_NONE) return;
@@ -356,6 +304,7 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
       gpr_arena_alloc(arena, GPR_ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_call)) +
                                  channel_stack->call_stack_size));
   gpr_ref_init(&call->ext_ref, 1);
+  gpr_atm_no_barrier_store(&call->cancelled, 0);
   call->arena = arena;
   grpc_call_combiner_init(&call->call_combiner);
   *out_call = call;
@@ -369,7 +318,6 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
   grpc_slice path = grpc_empty_slice();
   if (call->is_client) {
     GRPC_STATS_INC_CLIENT_CALLS_CREATED();
-    call->server = nullptr;
     GPR_ASSERT(args->add_initial_metadata_count <
                MAX_SEND_EXTRA_METADATA_COUNT);
     for (i = 0; i < args->add_initial_metadata_count; i++) {
@@ -384,7 +332,7 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
         static_cast<int>(args->add_initial_metadata_count);
   } else {
     GRPC_STATS_INC_SERVER_CALLS_CREATED();
-    call->server = args->server;
+    call->final_op.server.server = args->server;
     GPR_ASSERT(args->add_initial_metadata_count == 0);
     call->send_extra_metadata_count = 0;
   }
@@ -466,10 +414,10 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
     gpr_mu_unlock(&pc->child_list_mu);
   }
   if (error != GRPC_ERROR_NONE) {
-    cancel_with_error(call, STATUS_FROM_SURFACE, GRPC_ERROR_REF(error));
+    cancel_with_error(call, GRPC_ERROR_REF(error));
   }
   if (immediately_cancel) {
-    cancel_with_error(call, STATUS_FROM_API_OVERRIDE, GRPC_ERROR_CANCELLED);
+    cancel_with_error(call, GRPC_ERROR_CANCELLED);
   }
   if (args->cq != nullptr) {
     GPR_ASSERT(args->pollset_set_alternative == nullptr &&
@@ -496,7 +444,7 @@ grpc_error* grpc_call_create(const grpc_call_create_args* args,
     }
   } else {
     grpc_core::channelz::ServerNode* channelz_server =
-        grpc_server_get_channelz_node(call->server);
+        grpc_server_get_channelz_node(call->final_op.server.server);
     if (channelz_server != nullptr) {
       channelz_server->RecordCallStarted();
     }
@@ -571,16 +519,13 @@ static void destroy_call(void* call, grpc_error* error) {
     GRPC_CQ_INTERNAL_UNREF(c->cq, "bind");
   }
 
-  get_final_status(c, set_status_value_directly, &c->final_info.final_status,
-                   nullptr, &(c->final_info.error_string));
+  grpc_error_get_status(c->status_error, c->send_deadline,
+                        &c->final_info.final_status, nullptr, nullptr,
+                        &(c->final_info.error_string));
+  GRPC_ERROR_UNREF(c->status_error);
   c->final_info.stats.latency =
       gpr_time_sub(gpr_now(GPR_CLOCK_MONOTONIC), c->start_time);
 
-  for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-    GRPC_ERROR_UNREF(
-        unpack_received_status(gpr_atm_acq_load(&c->status[i])).error);
-  }
-
   grpc_call_stack_destroy(CALL_STACK_FROM_CALL(c), &c->final_info,
                           GRPC_CLOSURE_INIT(&c->release_call, release_call, c,
                                             grpc_schedule_on_exec_ctx));
@@ -618,7 +563,7 @@ void grpc_call_unref(grpc_call* c) {
   bool cancel = gpr_atm_acq_load(&c->any_ops_sent_atm) != 0 &&
                 gpr_atm_acq_load(&c->received_final_op_atm) == 0;
   if (cancel) {
-    cancel_with_error(c, STATUS_FROM_API_OVERRIDE, GRPC_ERROR_CANCELLED);
+    cancel_with_error(c, GRPC_ERROR_CANCELLED);
   } else {
     // Unset the call combiner cancellation closure.  This has the
     // effect of scheduling the previously set cancellation closure, if
@@ -636,8 +581,7 @@ grpc_call_error grpc_call_cancel(grpc_call* call, void* reserved) {
   GRPC_API_TRACE("grpc_call_cancel(call=%p, reserved=%p)", 2, (call, reserved));
   GPR_ASSERT(!reserved);
   grpc_core::ExecCtx exec_ctx;
-  cancel_with_error(call, STATUS_FROM_API_OVERRIDE, GRPC_ERROR_CANCELLED);
-
+  cancel_with_error(call, GRPC_ERROR_CANCELLED);
   return GRPC_CALL_OK;
 }
 
@@ -691,8 +635,7 @@ grpc_call_error grpc_call_cancel_with_status(grpc_call* c,
       "c=%p, status=%d, description=%s, reserved=%p)",
       4, (c, (int)status, description, reserved));
   GPR_ASSERT(reserved == nullptr);
-  cancel_with_status(c, STATUS_FROM_API_OVERRIDE, status, description);
-
+  cancel_with_status(c, status, description);
   return GRPC_CALL_OK;
 }
 
@@ -712,15 +655,17 @@ static void done_termination(void* arg, grpc_error* error) {
   gpr_free(state);
 }
 
-static void cancel_with_error(grpc_call* c, status_source source,
-                              grpc_error* error) {
+static void cancel_with_error(grpc_call* c, grpc_error* error) {
+  if (!gpr_atm_rel_cas(&c->cancelled, 0, 1)) {
+    GRPC_ERROR_UNREF(error);
+    return;
+  }
   GRPC_CALL_INTERNAL_REF(c, "termination");
   // Inform the call combiner of the cancellation, so that it can cancel
   // any in-flight asynchronous actions that may be holding the call
   // combiner.  This ensures that the cancel_stream batch can be sent
   // down the filter stack in a timely manner.
   grpc_call_combiner_cancel(&c->call_combiner, GRPC_ERROR_REF(error));
-  set_status_from_error(c, source, GRPC_ERROR_REF(error));
   cancel_state* state = static_cast<cancel_state*>(gpr_malloc(sizeof(*state)));
   state->call = c;
   GRPC_CLOSURE_INIT(&state->finish_batch, done_termination, state,
@@ -743,90 +688,45 @@ static grpc_error* error_from_status(grpc_status_code status,
       GRPC_ERROR_INT_GRPC_STATUS, status);
 }
 
-static void cancel_with_status(grpc_call* c, status_source source,
-                               grpc_status_code status,
+static void cancel_with_status(grpc_call* c, grpc_status_code status,
                                const char* description) {
-  cancel_with_error(c, source, error_from_status(status, description));
-}
-
-/*******************************************************************************
- * FINAL STATUS CODE MANIPULATION
- */
-
-static bool get_final_status_from(
-    grpc_call* call, grpc_error* error, bool allow_ok_status,
-    void (*set_value)(grpc_status_code code, void* user_data),
-    void* set_value_user_data, grpc_slice* details, const char** error_string) {
-  grpc_status_code code;
-  grpc_slice slice = grpc_empty_slice();
-  grpc_error_get_status(error, call->send_deadline, &code, &slice, nullptr,
-                        error_string);
-  if (code == GRPC_STATUS_OK && !allow_ok_status) {
-    return false;
-  }
-
-  set_value(code, set_value_user_data);
-  if (details != nullptr) {
-    *details = grpc_slice_ref_internal(slice);
-  }
-  return true;
+  cancel_with_error(c, error_from_status(status, description));
 }
 
-static void get_final_status(
-    grpc_call* call, void (*set_value)(grpc_status_code code, void* user_data),
-    void* set_value_user_data, grpc_slice* details, const char** error_string) {
-  int i;
-  received_status status[STATUS_SOURCE_COUNT];
-  for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-    status[i] = unpack_received_status(gpr_atm_acq_load(&call->status[i]));
-  }
+static void set_final_status(grpc_call* call, grpc_error* error) {
   if (grpc_call_error_trace.enabled()) {
-    gpr_log(GPR_INFO, "get_final_status %s", call->is_client ? "CLI" : "SVR");
-    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-      if (status[i].is_set) {
-        gpr_log(GPR_INFO, "  %d: %s", i, grpc_error_string(status[i].error));
-      }
-    }
+    gpr_log(GPR_DEBUG, "set_final_status %s", call->is_client ? "CLI" : "SVR");
+    gpr_log(GPR_DEBUG, "%s", grpc_error_string(error));
   }
-  /* first search through ignoring "OK" statuses: if something went wrong,
-   * ensure we report it */
-  for (int allow_ok_status = 0; allow_ok_status < 2; allow_ok_status++) {
-    /* search for the best status we can present: ideally the error we use has a
-       clearly defined grpc-status, and we'll prefer that. */
-    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-      if (status[i].is_set &&
-          grpc_error_has_clear_grpc_status(status[i].error)) {
-        if (get_final_status_from(call, status[i].error, allow_ok_status != 0,
-                                  set_value, set_value_user_data, details,
-                                  error_string)) {
-          return;
-        }
+  if (call->is_client) {
+    grpc_error_get_status(error, call->send_deadline,
+                          call->final_op.client.status,
+                          call->final_op.client.status_details, nullptr,
+                          call->final_op.client.error_string);
+    // explicitly take a ref
+    grpc_slice_ref_internal(*call->final_op.client.status_details);
+    call->status_error = error;
+    grpc_core::channelz::ChannelNode* channelz_channel =
+        grpc_channel_get_channelz_node(call->channel);
+    if (channelz_channel != nullptr) {
+      if (*call->final_op.client.status != GRPC_STATUS_OK) {
+        channelz_channel->RecordCallFailed();
+      } else {
+        channelz_channel->RecordCallSucceeded();
       }
     }
-    /* If no clearly defined status exists, search for 'anything' */
-    for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
-      if (status[i].is_set) {
-        if (get_final_status_from(call, status[i].error, allow_ok_status != 0,
-                                  set_value, set_value_user_data, details,
-                                  error_string)) {
-          return;
-        }
+  } else {
+    *call->final_op.server.cancelled =
+        error != GRPC_ERROR_NONE || call->status_error != GRPC_ERROR_NONE;
+    grpc_core::channelz::ServerNode* channelz_server =
+        grpc_server_get_channelz_node(call->final_op.server.server);
+    if (channelz_server != nullptr) {
+      if (*call->final_op.server.cancelled) {
+        channelz_server->RecordCallFailed();
+      } else {
+        channelz_server->RecordCallSucceeded();
       }
     }
-  }
-  /* If nothing exists, set some default */
-  if (call->is_client) {
-    set_value(GRPC_STATUS_UNKNOWN, set_value_user_data);
-  } else {
-    set_value(GRPC_STATUS_OK, set_value_user_data);
-  }
-}
-
-static void set_status_from_error(grpc_call* call, status_source source,
-                                  grpc_error* error) {
-  if (!gpr_atm_rel_cas(&call->status[source],
-                       pack_received_status({false, GRPC_ERROR_NONE}),
-                       pack_received_status({true, error}))) {
     GRPC_ERROR_UNREF(error);
   }
 }
@@ -1045,6 +945,7 @@ static grpc_stream_compression_algorithm decode_stream_compression(
 static void publish_app_metadata(grpc_call* call, grpc_metadata_batch* b,
                                  int is_trailing) {
   if (b->list.count == 0) return;
+  if (!call->is_client && is_trailing) return;
   if (is_trailing && call->buffered_metadata[1] == nullptr) return;
   GPR_TIMER_SCOPE("publish_app_metadata", 0);
   grpc_metadata_array* dest;
@@ -1098,9 +999,12 @@ static void recv_initial_filter(grpc_call* call, grpc_metadata_batch* b) {
   publish_app_metadata(call, b, false);
 }
 
-static void recv_trailing_filter(void* args, grpc_metadata_batch* b) {
+static void recv_trailing_filter(void* args, grpc_metadata_batch* b,
+                                 grpc_error* batch_error) {
   grpc_call* call = static_cast<grpc_call*>(args);
-  if (b->idx.named.grpc_status != nullptr) {
+  if (batch_error != GRPC_ERROR_NONE) {
+    set_final_status(call, batch_error);
+  } else if (b->idx.named.grpc_status != nullptr) {
     grpc_status_code status_code =
         grpc_get_status_code_from_metadata(b->idx.named.grpc_status->md);
     grpc_error* error = GRPC_ERROR_NONE;
@@ -1118,8 +1022,18 @@ static void recv_trailing_filter(void* args, grpc_metadata_batch* b) {
       error = grpc_error_set_str(error, GRPC_ERROR_STR_GRPC_MESSAGE,
                                  grpc_empty_slice());
     }
-    set_status_from_error(call, STATUS_FROM_WIRE, error);
+    set_final_status(call, GRPC_ERROR_REF(error));
     grpc_metadata_batch_remove(b, b->idx.named.grpc_status);
+    GRPC_ERROR_UNREF(error);
+  } else if (!call->is_client) {
+    set_final_status(call, GRPC_ERROR_NONE);
+  } else {
+    gpr_log(GPR_DEBUG,
+            "Received trailing metadata with no error and no status");
+    set_final_status(
+        call, grpc_error_set_int(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("No status received"),
+                  GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNKNOWN));
   }
   publish_app_metadata(call, b, true);
 }
@@ -1134,14 +1048,6 @@ grpc_call_stack* grpc_call_get_call_stack(grpc_call* call) {
  * BATCH API IMPLEMENTATION
  */
 
-static void set_status_value_directly(grpc_status_code status, void* dest) {
-  *static_cast<grpc_status_code*>(dest) = status;
-}
-
-static void set_cancelled_value(grpc_status_code status, void* dest) {
-  *static_cast<int*>(dest) = (status != GRPC_STATUS_OK);
-}
-
 static bool are_write_flags_valid(uint32_t flags) {
   /* check that only bits in GRPC_WRITE_(INTERNAL?)_USED_MASK are set */
   const uint32_t allowed_write_positions =
@@ -1209,31 +1115,15 @@ static void finish_batch_completion(void* user_data,
   GRPC_CALL_INTERNAL_UNREF(call, "completion");
 }
 
-static grpc_error* consolidate_batch_errors(batch_control* bctl) {
-  size_t n = static_cast<size_t>(gpr_atm_acq_load(&bctl->num_errors));
-  if (n == 0) {
-    return GRPC_ERROR_NONE;
-  } else if (n == 1) {
-    /* Skip creating a composite error in the case that only one error was
-       logged */
-    grpc_error* e = bctl->errors[0];
-    bctl->errors[0] = nullptr;
-    return e;
-  } else {
-    grpc_error* error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-        "Call batch failed", bctl->errors, n);
-    for (size_t i = 0; i < n; i++) {
-      GRPC_ERROR_UNREF(bctl->errors[i]);
-      bctl->errors[i] = nullptr;
-    }
-    return error;
-  }
+static void reset_batch_errors(batch_control* bctl) {
+  GRPC_ERROR_UNREF(bctl->batch_error);
+  bctl->batch_error = GRPC_ERROR_NONE;
 }
 
 static void post_batch_completion(batch_control* bctl) {
   grpc_call* next_child_call;
   grpc_call* call = bctl->call;
-  grpc_error* error = consolidate_batch_errors(bctl);
+  grpc_error* error = GRPC_ERROR_REF(bctl->batch_error);
 
   if (bctl->op.send_initial_metadata) {
     grpc_metadata_batch_destroy(
@@ -1259,8 +1149,7 @@ static void post_batch_completion(batch_control* bctl) {
           next_child_call = child->child->sibling_next;
           if (child->cancellation_is_inherited) {
             GRPC_CALL_INTERNAL_REF(child, "propagate_cancel");
-            cancel_with_error(child, STATUS_FROM_API_OVERRIDE,
-                              GRPC_ERROR_CANCELLED);
+            cancel_with_error(child, GRPC_ERROR_CANCELLED);
             GRPC_CALL_INTERNAL_UNREF(child, "propagate_cancel");
           }
           child = next_child_call;
@@ -1268,33 +1157,6 @@ static void post_batch_completion(batch_control* bctl) {
       }
       gpr_mu_unlock(&pc->child_list_mu);
     }
-    if (call->is_client) {
-      get_final_status(call, set_status_value_directly,
-                       call->final_op.client.status,
-                       call->final_op.client.status_details,
-                       call->final_op.client.error_string);
-      grpc_core::channelz::ChannelNode* channelz_channel =
-          grpc_channel_get_channelz_node(call->channel);
-      if (channelz_channel != nullptr) {
-        if (*call->final_op.client.status != GRPC_STATUS_OK) {
-          channelz_channel->RecordCallFailed();
-        } else {
-          channelz_channel->RecordCallSucceeded();
-        }
-      }
-    } else {
-      get_final_status(call, set_cancelled_value,
-                       call->final_op.server.cancelled, nullptr, nullptr);
-      grpc_core::channelz::ServerNode* channelz_server =
-          grpc_server_get_channelz_node(call->server);
-      if (channelz_server != nullptr) {
-        if (*call->final_op.server.cancelled) {
-          channelz_server->RecordCallFailed();
-        } else {
-          channelz_server->RecordCallSucceeded();
-        }
-      }
-    }
     GRPC_ERROR_UNREF(error);
     error = GRPC_ERROR_NONE;
   }
@@ -1303,9 +1165,10 @@ static void post_batch_completion(batch_control* bctl) {
     grpc_byte_buffer_destroy(*call->receiving_buffer);
     *call->receiving_buffer = nullptr;
   }
+  reset_batch_errors(bctl);
 
   if (bctl->completion_data.notify_tag.is_closure) {
-    /* unrefs bctl->error */
+    /* unrefs error */
     bctl->call = nullptr;
     /* This closure may be meant to be run within some combiner. Since we aren't
      * running in any combiner here, we need to use GRPC_CLOSURE_SCHED instead
@@ -1315,7 +1178,7 @@ static void post_batch_completion(batch_control* bctl) {
                        error);
     GRPC_CALL_INTERNAL_UNREF(call, "completion");
   } else {
-    /* unrefs bctl->error */
+    /* unrefs error */
     grpc_cq_end_op(bctl->call->cq, bctl->completion_data.notify_tag.tag, error,
                    finish_batch_completion, bctl,
                    &bctl->completion_data.cq_completion);
@@ -1424,8 +1287,10 @@ static void receiving_stream_ready(void* bctlp, grpc_error* error) {
   grpc_call* call = bctl->call;
   if (error != GRPC_ERROR_NONE) {
     call->receiving_stream.reset();
-    add_batch_error(bctl, GRPC_ERROR_REF(error), true);
-    cancel_with_error(call, STATUS_FROM_SURFACE, GRPC_ERROR_REF(error));
+    if (bctl->batch_error == GRPC_ERROR_NONE) {
+      bctl->batch_error = GRPC_ERROR_REF(error);
+    }
+    cancel_with_error(call, GRPC_ERROR_REF(error));
   }
   /* If recv_state is RECV_NONE, we will save the batch_control
    * object with rel_cas, and will not use it after the cas. Its corresponding
@@ -1443,7 +1308,7 @@ static void receiving_stream_ready_in_call_combiner(void* bctlp,
                                                     grpc_error* error) {
   batch_control* bctl = static_cast<batch_control*>(bctlp);
   grpc_call* call = bctl->call;
-  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "call_recv_message_ready");
+  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "recv_message_ready");
   receiving_stream_ready(bctlp, error);
 }
 
@@ -1461,8 +1326,7 @@ static void validate_filtered_metadata(batch_control* bctl) {
                  call->incoming_stream_compression_algorithm,
                  call->incoming_message_compression_algorithm);
     gpr_log(GPR_ERROR, "%s", error_msg);
-    cancel_with_status(call, STATUS_FROM_SURFACE, GRPC_STATUS_INTERNAL,
-                       error_msg);
+    cancel_with_status(call, GRPC_STATUS_INTERNAL, error_msg);
     gpr_free(error_msg);
   } else if (
       grpc_compression_algorithm_from_message_stream_compression_algorithm(
@@ -1474,8 +1338,7 @@ static void validate_filtered_metadata(batch_control* bctl) {
                  "compression (%d).",
                  call->incoming_stream_compression_algorithm,
                  call->incoming_message_compression_algorithm);
-    cancel_with_status(call, STATUS_FROM_SURFACE, GRPC_STATUS_INTERNAL,
-                       error_msg);
+    cancel_with_status(call, GRPC_STATUS_INTERNAL, error_msg);
     gpr_free(error_msg);
   } else {
     char* error_msg = nullptr;
@@ -1485,8 +1348,7 @@ static void validate_filtered_metadata(batch_control* bctl) {
       gpr_asprintf(&error_msg, "Invalid compression algorithm value '%d'.",
                    compression_algorithm);
       gpr_log(GPR_ERROR, "%s", error_msg);
-      cancel_with_status(call, STATUS_FROM_SURFACE, GRPC_STATUS_UNIMPLEMENTED,
-                         error_msg);
+      cancel_with_status(call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
     } else if (grpc_compression_options_is_algorithm_enabled(
                    &compression_options, compression_algorithm) == 0) {
       /* check if algorithm is supported by current channel config */
@@ -1495,8 +1357,7 @@ static void validate_filtered_metadata(batch_control* bctl) {
       gpr_asprintf(&error_msg, "Compression algorithm '%s' is disabled.",
                    algo_name);
       gpr_log(GPR_ERROR, "%s", error_msg);
-      cancel_with_status(call, STATUS_FROM_SURFACE, GRPC_STATUS_UNIMPLEMENTED,
-                         error_msg);
+      cancel_with_status(call, GRPC_STATUS_UNIMPLEMENTED, error_msg);
     }
     gpr_free(error_msg);
 
@@ -1514,24 +1375,12 @@ static void validate_filtered_metadata(batch_control* bctl) {
   }
 }
 
-static void add_batch_error(batch_control* bctl, grpc_error* error,
-                            bool has_cancelled) {
-  if (error == GRPC_ERROR_NONE) return;
-  int idx = static_cast<int>(gpr_atm_full_fetch_add(&bctl->num_errors, 1));
-  if (idx == 0 && !has_cancelled) {
-    cancel_with_error(bctl->call, STATUS_FROM_CORE, GRPC_ERROR_REF(error));
-  }
-  bctl->errors[idx] = error;
-}
-
 static void receiving_initial_metadata_ready(void* bctlp, grpc_error* error) {
   batch_control* bctl = static_cast<batch_control*>(bctlp);
   grpc_call* call = bctl->call;
 
-  GRPC_CALL_COMBINER_STOP(&call->call_combiner,
-                          "call_recv_initial_metadata_ready");
+  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "recv_initial_metadata_ready");
 
-  add_batch_error(bctl, GRPC_ERROR_REF(error), false);
   if (error == GRPC_ERROR_NONE) {
     grpc_metadata_batch* md =
         &call->metadata_batch[1 /* is_receiving */][0 /* is_trailing */];
@@ -1544,6 +1393,11 @@ static void receiving_initial_metadata_ready(void* bctlp, grpc_error* error) {
     if (md->deadline != GRPC_MILLIS_INF_FUTURE && !call->is_client) {
       call->send_deadline = md->deadline;
     }
+  } else {
+    if (bctl->batch_error == GRPC_ERROR_NONE) {
+      bctl->batch_error = GRPC_ERROR_REF(error);
+    }
+    cancel_with_error(call, GRPC_ERROR_REF(error));
   }
 
   grpc_closure* saved_rsr_closure = nullptr;
@@ -1580,20 +1434,23 @@ static void receiving_initial_metadata_ready(void* bctlp, grpc_error* error) {
 static void receiving_trailing_metadata_ready(void* bctlp, grpc_error* error) {
   batch_control* bctl = static_cast<batch_control*>(bctlp);
   grpc_call* call = bctl->call;
-  GRPC_CALL_COMBINER_STOP(&call->call_combiner,
-                          "call_recv_trailing_metadata_ready");
-  add_batch_error(bctl, GRPC_ERROR_REF(error), false);
+  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "recv_trailing_metadata_ready");
   grpc_metadata_batch* md =
       &call->metadata_batch[1 /* is_receiving */][1 /* is_trailing */];
-  recv_trailing_filter(call, md);
+  recv_trailing_filter(call, md, GRPC_ERROR_REF(error));
   finish_batch_step(bctl);
 }
 
 static void finish_batch(void* bctlp, grpc_error* error) {
   batch_control* bctl = static_cast<batch_control*>(bctlp);
   grpc_call* call = bctl->call;
-  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "call_on_complete");
-  add_batch_error(bctl, GRPC_ERROR_REF(error), false);
+  GRPC_CALL_COMBINER_STOP(&call->call_combiner, "on_complete");
+  if (bctl->batch_error == GRPC_ERROR_NONE) {
+    bctl->batch_error = GRPC_ERROR_REF(error);
+  }
+  if (error != GRPC_ERROR_NONE) {
+    cancel_with_error(call, GRPC_ERROR_REF(error));
+  }
   finish_batch_step(bctl);
 }
 
@@ -1795,28 +1652,32 @@ static grpc_call_error call_start_batch(grpc_call* call, const grpc_op* ops,
         call->send_extra_metadata_count = 1;
         call->send_extra_metadata[0].md = grpc_channel_get_reffed_status_elem(
             call->channel, op->data.send_status_from_server.status);
-        {
-          grpc_error* override_error = GRPC_ERROR_NONE;
-          if (op->data.send_status_from_server.status != GRPC_STATUS_OK) {
-            override_error =
-                error_from_status(op->data.send_status_from_server.status,
-                                  "Returned non-ok status");
-          }
-          if (op->data.send_status_from_server.status_details != nullptr) {
-            call->send_extra_metadata[1].md = grpc_mdelem_from_slices(
-                GRPC_MDSTR_GRPC_MESSAGE,
-                grpc_slice_ref_internal(
-                    *op->data.send_status_from_server.status_details));
-            call->send_extra_metadata_count++;
+        grpc_error* status_error =
+            op->data.send_status_from_server.status == GRPC_STATUS_OK
+                ? GRPC_ERROR_NONE
+                : grpc_error_set_int(
+                      GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                          "Server returned error"),
+                      GRPC_ERROR_INT_GRPC_STATUS,
+                      static_cast<intptr_t>(
+                          op->data.send_status_from_server.status));
+        if (op->data.send_status_from_server.status_details != nullptr) {
+          call->send_extra_metadata[1].md = grpc_mdelem_from_slices(
+              GRPC_MDSTR_GRPC_MESSAGE,
+              grpc_slice_ref_internal(
+                  *op->data.send_status_from_server.status_details));
+          call->send_extra_metadata_count++;
+          if (status_error != GRPC_ERROR_NONE) {
             char* msg = grpc_slice_to_c_string(
                 GRPC_MDVALUE(call->send_extra_metadata[1].md));
-            override_error =
-                grpc_error_set_str(override_error, GRPC_ERROR_STR_GRPC_MESSAGE,
+            status_error =
+                grpc_error_set_str(status_error, GRPC_ERROR_STR_GRPC_MESSAGE,
                                    grpc_slice_from_copied_string(msg));
             gpr_free(msg);
           }
-          set_status_from_error(call, STATUS_FROM_API_OVERRIDE, override_error);
         }
+
+        call->status_error = status_error;
         if (!prepare_application_metadata(
                 call,
                 static_cast<int>(

src/core/lib/surface/channel.cc

@@ -100,7 +100,6 @@ grpc_channel* grpc_channel_create_with_builder(
     return channel;
   }
 
-  memset(channel, 0, sizeof(*channel));
   channel->target = target;
   channel->is_client = grpc_channel_stack_type_is_client(channel_stack_type);
   size_t channel_tracer_max_nodes = 0;  // default to off
@@ -166,8 +165,8 @@ grpc_channel* grpc_channel_create_with_builder(
   }
 
   grpc_channel_args_destroy(args);
-  // only track client channels since server channels are held in the
-  // grpc_server channel.
+  // we only need to do the channelz bookkeeping for clients here. The channelz
+  // bookkeeping for server channels occurs in src/core/lib/surface/server.cc
   if (channelz_enabled && channel->is_client) {
     channel->channelz_channel = channel_node_create_func(
         channel, channel_tracer_max_nodes, !internal_channel);

src/core/lib/surface/server.cc

@@ -149,6 +149,9 @@ struct call_data {
   grpc_closure server_on_recv_initial_metadata;
   grpc_closure kill_zombie_closure;
   grpc_closure* on_done_recv_initial_metadata;
+  grpc_closure recv_trailing_metadata_ready;
+  grpc_error* error;
+  grpc_closure* original_recv_trailing_metadata_ready;
 
   grpc_closure publish;
 
@@ -733,6 +736,14 @@ static void server_on_recv_initial_metadata(void* ptr, grpc_error* error) {
   GRPC_CLOSURE_RUN(calld->on_done_recv_initial_metadata, error);
 }
 
+static void server_recv_trailing_metadata_ready(void* user_data,
+                                                grpc_error* err) {
+  grpc_call_element* elem = static_cast<grpc_call_element*>(user_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  err = grpc_error_add_child(GRPC_ERROR_REF(err), GRPC_ERROR_REF(calld->error));
+  GRPC_CLOSURE_RUN(calld->original_recv_trailing_metadata_ready, err);
+}
+
 static void server_mutate_op(grpc_call_element* elem,
                              grpc_transport_stream_op_batch* op) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
@@ -748,6 +759,12 @@ static void server_mutate_op(grpc_call_element* elem,
     op->payload->recv_initial_metadata.recv_flags =
         &calld->recv_initial_metadata_flags;
   }
+  if (op->recv_trailing_metadata) {
+    calld->original_recv_trailing_metadata_ready =
+        op->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
+    op->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
+        &calld->recv_trailing_metadata_ready;
+  }
 }
 
 static void server_start_transport_stream_op_batch(
@@ -832,7 +849,9 @@ static grpc_error* init_call_elem(grpc_call_element* elem,
   GRPC_CLOSURE_INIT(&calld->server_on_recv_initial_metadata,
                     server_on_recv_initial_metadata, elem,
                     grpc_schedule_on_exec_ctx);
-
+  GRPC_CLOSURE_INIT(&calld->recv_trailing_metadata_ready,
+                    server_recv_trailing_metadata_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   server_ref(chand->server);
   return GRPC_ERROR_NONE;
 }
@@ -844,7 +863,7 @@ static void destroy_call_elem(grpc_call_element* elem,
   call_data* calld = static_cast<call_data*>(elem->call_data);
 
   GPR_ASSERT(calld->state != PENDING);
-
+  GRPC_ERROR_UNREF(calld->error);
   if (calld->host_set) {
     grpc_slice_unref_internal(calld->host);
   }

src/core/tsi/alts/handshaker/alts_handshaker_client.cc

@@ -24,6 +24,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/tsi/alts/handshaker/alts_handshaker_service_api.h"
 
 const int kHandshakerClientOpNum = 4;
@@ -109,7 +110,7 @@ static grpc_byte_buffer* get_serialized_start_client(alts_tsi_event* event) {
   if (ok) {
     buffer = grpc_raw_byte_buffer_create(&slice, 1 /* number of slices */);
   }
-  grpc_slice_unref(slice);
+  grpc_slice_unref_internal(slice);
   gpr_free(target_name);
   grpc_gcp_handshaker_req_destroy(req);
   return buffer;
@@ -157,7 +158,7 @@ static grpc_byte_buffer* get_serialized_start_server(
   if (ok) {
     buffer = grpc_raw_byte_buffer_create(&req_slice, 1 /* number of slices */);
   }
-  grpc_slice_unref(req_slice);
+  grpc_slice_unref_internal(req_slice);
   grpc_gcp_handshaker_req_destroy(req);
   return buffer;
 }
@@ -195,7 +196,7 @@ static grpc_byte_buffer* get_serialized_next(grpc_slice* bytes_received) {
   if (ok) {
     buffer = grpc_raw_byte_buffer_create(&req_slice, 1 /* number of slices */);
   }
-  grpc_slice_unref(req_slice);
+  grpc_slice_unref_internal(req_slice);
   grpc_gcp_handshaker_req_destroy(req);
   return buffer;
 }
@@ -258,7 +259,7 @@ alts_handshaker_client* alts_grpc_handshaker_client_create(
       grpc_slice_from_static_string(ALTS_SERVICE_METHOD), &slice,
       gpr_inf_future(GPR_CLOCK_REALTIME), nullptr);
   client->base.vtable = &vtable;
-  grpc_slice_unref(slice);
+  grpc_slice_unref_internal(slice);
   return &client->base;
 }
 

src/core/tsi/alts/handshaker/alts_handshaker_service_api_util.cc

@@ -20,6 +20,8 @@
 
 #include "src/core/tsi/alts/handshaker/alts_handshaker_service_api_util.h"
 
+#include "src/core/lib/slice/slice_internal.h"
+
 void add_repeated_field(repeated_field** head, const void* data) {
   repeated_field* field =
       static_cast<repeated_field*>(gpr_zalloc(sizeof(*field)));
@@ -67,7 +69,7 @@ grpc_slice* create_slice(const char* data, size_t size) {
 
 void destroy_slice(grpc_slice* slice) {
   if (slice != nullptr) {
-    grpc_slice_unref(*slice);
+    grpc_slice_unref_internal(*slice);
     gpr_free(slice);
   }
 }

src/core/tsi/alts/handshaker/alts_tsi_event.cc

@@ -24,6 +24,8 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 tsi_result alts_tsi_event_create(alts_tsi_handshaker* handshaker,
                                  tsi_handshaker_on_next_done_cb cb,
                                  void* user_data,
@@ -66,8 +68,8 @@ void alts_tsi_event_destroy(alts_tsi_event* event) {
   grpc_byte_buffer_destroy(event->recv_buffer);
   grpc_metadata_array_destroy(&event->initial_metadata);
   grpc_metadata_array_destroy(&event->trailing_metadata);
-  grpc_slice_unref(event->details);
-  grpc_slice_unref(event->target_name);
+  grpc_slice_unref_internal(event->details);
+  grpc_slice_unref_internal(event->target_name);
   grpc_alts_credentials_options_destroy(event->options);
   gpr_free(event);
 }

src/core/tsi/alts/handshaker/alts_tsi_handshaker.cc

@@ -31,6 +31,7 @@
 
 #include "src/core/lib/gpr/host_port.h"
 #include "src/core/lib/gprpp/thd.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/tsi/alts/frame_protector/alts_frame_protector.h"
 #include "src/core/tsi/alts/handshaker/alts_handshaker_client.h"
 #include "src/core/tsi/alts/handshaker/alts_tsi_utils.h"
@@ -182,7 +183,7 @@ static void handshaker_result_destroy(tsi_handshaker_result* self) {
   gpr_free(result->peer_identity);
   gpr_free(result->key_data);
   gpr_free(result->unused_bytes);
-  grpc_slice_unref(result->rpc_versions);
+  grpc_slice_unref_internal(result->rpc_versions);
   gpr_free(result);
 }
 
@@ -269,12 +270,12 @@ static tsi_result handshaker_next(
     handshaker->has_sent_start_message = true;
   } else {
     if (!GRPC_SLICE_IS_EMPTY(handshaker->recv_bytes)) {
-      grpc_slice_unref(handshaker->recv_bytes);
+      grpc_slice_unref_internal(handshaker->recv_bytes);
     }
     handshaker->recv_bytes = grpc_slice_ref(slice);
     ok = alts_handshaker_client_next(handshaker->client, event, &slice);
   }
-  grpc_slice_unref(slice);
+  grpc_slice_unref_internal(slice);
   if (ok != TSI_OK) {
     gpr_log(GPR_ERROR, "Failed to schedule ALTS handshaker requests");
     return ok;
@@ -299,8 +300,8 @@ static void handshaker_destroy(tsi_handshaker* self) {
   alts_tsi_handshaker* handshaker =
       reinterpret_cast<alts_tsi_handshaker*>(self);
   alts_handshaker_client_destroy(handshaker->client);
-  grpc_slice_unref(handshaker->recv_bytes);
-  grpc_slice_unref(handshaker->target_name);
+  grpc_slice_unref_internal(handshaker->recv_bytes);
+  grpc_slice_unref_internal(handshaker->target_name);
   grpc_alts_credentials_options_destroy(handshaker->options);
   gpr_free(handshaker->buffer);
   gpr_free(handshaker);

src/core/tsi/alts/handshaker/alts_tsi_utils.cc

@@ -22,6 +22,8 @@
 
 #include <grpc/byte_buffer_reader.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 tsi_result alts_tsi_utils_convert_to_tsi_result(grpc_status_code code) {
   switch (code) {
     case GRPC_STATUS_OK:
@@ -47,7 +49,7 @@ grpc_gcp_handshaker_resp* alts_tsi_utils_deserialize_response(
   grpc_slice slice = grpc_byte_buffer_reader_readall(&bbr);
   grpc_gcp_handshaker_resp* resp = grpc_gcp_handshaker_resp_create();
   bool ok = grpc_gcp_handshaker_resp_decode(slice, resp);
-  grpc_slice_unref(slice);
+  grpc_slice_unref_internal(slice);
   grpc_byte_buffer_reader_destroy(&bbr);
   if (!ok) {
     grpc_gcp_handshaker_resp_destroy(resp);

src/core/tsi/alts/zero_copy_frame_protector/alts_grpc_privacy_integrity_record_protocol.cc

@@ -61,7 +61,7 @@ static tsi_result alts_grpc_privacy_integrity_protect(
   if (status != GRPC_STATUS_OK) {
     gpr_log(GPR_ERROR, "Failed to protect, %s", error_details);
     gpr_free(error_details);
-    grpc_slice_unref(protected_slice);
+    grpc_slice_unref_internal(protected_slice);
     return TSI_INTERNAL_ERROR;
   }
   grpc_slice_buffer_add(protected_slices, protected_slice);
@@ -106,7 +106,7 @@ static tsi_result alts_grpc_privacy_integrity_unprotect(
   if (status != GRPC_STATUS_OK) {
     gpr_log(GPR_ERROR, "Failed to unprotect, %s", error_details);
     gpr_free(error_details);
-    grpc_slice_unref(unprotected_slice);
+    grpc_slice_unref_internal(unprotected_slice);
     return TSI_INTERNAL_ERROR;
   }
   grpc_slice_buffer_reset_and_unref_internal(&rp->header_sb);

src/core/tsi/alts_transport_security.cc

@@ -45,7 +45,9 @@ void grpc_tsi_alts_signal_for_cq_destroy() {
 }
 
 void grpc_tsi_alts_init() {
-  memset(&g_alts_resource, 0, sizeof(alts_shared_resource));
+  g_alts_resource.channel = nullptr;
+  g_alts_resource.cq = nullptr;
+  g_alts_resource.is_cq_drained = false;
   gpr_mu_init(&g_alts_resource.mu);
   gpr_cv_init(&g_alts_resource.cv);
 }

src/core/tsi/ssl/session_cache/ssl_session_cache.cc

@@ -19,6 +19,7 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/gprpp/mutex_lock.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/tsi/ssl/session_cache/ssl_session.h"
 #include "src/core/tsi/ssl/session_cache/ssl_session_cache.h"
 
@@ -53,7 +54,7 @@ class SslSessionLRUCache::Node {
     SetSession(std::move(session));
   }
 
-  ~Node() { grpc_slice_unref(key_); }
+  ~Node() { grpc_slice_unref_internal(key_); }
 
   // Not copyable nor movable.
   Node(const Node&) = delete;

src/cpp/server/health/default_health_check_service.cc

@@ -289,13 +289,13 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::CheckCallHandler::
   grpc::Status status = Status::OK;
   ByteBuffer response;
   if (!service_->DecodeRequest(request_, &service_name)) {
-    status = Status(INVALID_ARGUMENT, "");
+    status = Status(StatusCode::INVALID_ARGUMENT, "");
   } else {
     ServingStatus serving_status = database_->GetServingStatus(service_name);
     if (serving_status == NOT_FOUND) {
       status = Status(StatusCode::NOT_FOUND, "service name unknown");
     } else if (!service_->EncodeResponse(serving_status, &response)) {
-      status = Status(INTERNAL, "");
+      status = Status(StatusCode::INTERNAL, "");
     }
   }
   // Send response.
@@ -389,7 +389,7 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::WatchCallHandler::
         CallableTag(std::bind(&WatchCallHandler::OnFinishDone, this,
                               std::placeholders::_1, std::placeholders::_2),
                     std::move(self));
-    stream_.Finish(Status(INVALID_ARGUMENT, ""), &on_finish_done_);
+    stream_.Finish(Status(StatusCode::INVALID_ARGUMENT, ""), &on_finish_done_);
     call_state_ = FINISH_CALLED;
     return;
   }
@@ -431,7 +431,7 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::WatchCallHandler::
         CallableTag(std::bind(&WatchCallHandler::OnFinishDone, this,
                               std::placeholders::_1, std::placeholders::_2),
                     std::move(self));
-    stream_.Finish(Status(INTERNAL, ""), &on_finish_done_);
+    stream_.Finish(Status(StatusCode::INTERNAL, ""), &on_finish_done_);
     return;
   }
   next_ = CallableTag(std::bind(&WatchCallHandler::OnSendHealthDone, this,

src/cpp/server/server_cc.cc

@@ -697,9 +697,6 @@ ServerInterface::BaseAsyncRequest::~BaseAsyncRequest() {
 
 bool ServerInterface::BaseAsyncRequest::FinalizeResult(void** tag,
                                                        bool* status) {
-  if (*status) {
-    context_->client_metadata_.FillMap();
-  }
   context_->set_call(call_);
   context_->cq_ = call_cq_;
   internal::Call call(call_, server_, call_cq_,

src/cpp/server/server_context.cc

@@ -134,7 +134,6 @@ ServerContext::ServerContext(gpr_timespec deadline, grpc_metadata_array* arr)
       compression_level_set_(false),
       has_pending_ops_(false) {
   std::swap(*client_metadata_.arr(), *arr);
-  client_metadata_.FillMap();
 }
 
 ServerContext::~ServerContext() {

src/csharp/Grpc.Core.Tests/ChannelConnectivityTest.cs

@@ -57,19 +57,23 @@ namespace Grpc.Core.Tests
         [Test]
         public async Task Channel_WaitForStateChangedAsync()
         {
-            helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
-            {
-                return Task.FromResult(request);
-            });
-
             Assert.ThrowsAsync(typeof(TaskCanceledException), 
-                async () => await channel.WaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(10)));
+                async () => await channel.WaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(0)));
 
             var stateChangedTask = channel.WaitForStateChangedAsync(channel.State);
+            await channel.ConnectAsync(DateTime.UtcNow.AddMilliseconds(5000));
+            await stateChangedTask;
+            Assert.AreEqual(ChannelState.Ready, channel.State);
+        }
 
-            await Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "abc");
+        [Test]
+        public async Task Channel_TryWaitForStateChangedAsync()
+        {
+            Assert.IsFalse(await channel.TryWaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(0)));
 
-            await stateChangedTask;
+            var stateChangedTask = channel.TryWaitForStateChangedAsync(channel.State);
+            await channel.ConnectAsync(DateTime.UtcNow.AddMilliseconds(5000));
+            Assert.IsTrue(await stateChangedTask);
             Assert.AreEqual(ChannelState.Ready, channel.State);
         }
 

src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs

@@ -106,6 +106,42 @@ namespace Grpc.Core.Internal.Tests
             AssertUnaryResponseError(asyncCall, fakeCall, resultTask, StatusCode.Internal);
         }
 
+        [Test]
+        public void AsyncUnary_RequestSerializationExceptionDoesntLeakResources()
+        {
+            string nullRequest = null;  // will throw when serializing
+            Assert.Throws(typeof(ArgumentNullException), () => asyncCall.UnaryCallAsync(nullRequest));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
+        [Test]
+        public void AsyncUnary_StartCallFailureDoesntLeakResources()
+        {
+            fakeCall.MakeStartCallFail();
+            Assert.Throws(typeof(InvalidOperationException), () => asyncCall.UnaryCallAsync("request1"));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
+        [Test]
+        public void SyncUnary_RequestSerializationExceptionDoesntLeakResources()
+        {
+            string nullRequest = null;  // will throw when serializing
+            Assert.Throws(typeof(ArgumentNullException), () => asyncCall.UnaryCall(nullRequest));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
+        [Test]
+        public void SyncUnary_StartCallFailureDoesntLeakResources()
+        {
+            fakeCall.MakeStartCallFail();
+            Assert.Throws(typeof(InvalidOperationException), () => asyncCall.UnaryCall("request1"));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
         [Test]
         public void ClientStreaming_StreamingReadNotAllowed()
         {
@@ -327,6 +363,15 @@ namespace Grpc.Core.Internal.Tests
             AssertUnaryResponseError(asyncCall, fakeCall, resultTask, StatusCode.Cancelled);
         }
 
+        [Test]
+        public void ClientStreaming_StartCallFailureDoesntLeakResources()
+        {
+            fakeCall.MakeStartCallFail();
+            Assert.Throws(typeof(InvalidOperationException), () => asyncCall.ClientStreamingCallAsync());
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
         [Test]
         public void ServerStreaming_StreamingSendNotAllowed()
         {
@@ -401,6 +446,27 @@ namespace Grpc.Core.Internal.Tests
             AssertStreamingResponseSuccess(asyncCall, fakeCall, readTask3);
         }
 
+        [Test]
+        public void ServerStreaming_RequestSerializationExceptionDoesntLeakResources()
+        {
+            string nullRequest = null;  // will throw when serializing
+            Assert.Throws(typeof(ArgumentNullException), () => asyncCall.StartServerStreamingCall(nullRequest));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+
+            var responseStream = new ClientResponseStream<string, string>(asyncCall);
+            var readTask = responseStream.MoveNext();
+        }
+
+        [Test]
+        public void ServerStreaming_StartCallFailureDoesntLeakResources()
+        {
+            fakeCall.MakeStartCallFail();
+            Assert.Throws(typeof(InvalidOperationException), () => asyncCall.StartServerStreamingCall("request1"));
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
         [Test]
         public void DuplexStreaming_NoRequestNoResponse_Success()
         {
@@ -558,6 +624,15 @@ namespace Grpc.Core.Internal.Tests
             AssertStreamingResponseError(asyncCall, fakeCall, readTask2, StatusCode.Cancelled);
         }
 
+        [Test]
+        public void DuplexStreaming_StartCallFailureDoesntLeakResources()
+        {
+            fakeCall.MakeStartCallFail();
+            Assert.Throws(typeof(InvalidOperationException), () => asyncCall.StartDuplexStreamingCall());
+            Assert.AreEqual(0, channel.GetCallReferenceCount());
+            Assert.IsTrue(fakeCall.IsDisposed);
+        }
+
         ClientSideStatus CreateClientSideStatus(StatusCode statusCode)
         {
             return new ClientSideStatus(new Status(statusCode, ""), new Metadata());

src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs

@@ -31,6 +31,7 @@ namespace Grpc.Core.Internal.Tests
     /// </summary>
     internal class FakeNativeCall : INativeCall
     {
+        private bool shouldStartCallFail;
         public IUnaryResponseClientCallback UnaryResponseClientCallback
         {
             get;
@@ -102,26 +103,31 @@ namespace Grpc.Core.Internal.Tests
 
         public void StartUnary(IUnaryResponseClientCallback callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
+            StartCallMaybeFail();
             UnaryResponseClientCallback = callback;
         }
 
         public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
+            StartCallMaybeFail();
             throw new NotImplementedException();
         }
 
         public void StartClientStreaming(IUnaryResponseClientCallback callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
+            StartCallMaybeFail();
             UnaryResponseClientCallback = callback;
         }
 
         public void StartServerStreaming(IReceivedStatusOnClientCallback callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
+            StartCallMaybeFail();
             ReceivedStatusOnClientCallback = callback;
         }
 
         public void StartDuplexStreaming(IReceivedStatusOnClientCallback callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
+            StartCallMaybeFail();
             ReceivedStatusOnClientCallback = callback;
         }
 
@@ -165,5 +171,22 @@ namespace Grpc.Core.Internal.Tests
         {
             IsDisposed = true;
         }
+
+        /// <summary>
+        /// Emulate CallSafeHandle.CheckOk() failure for all future attempts
+        /// to start a call.
+        /// </summary>
+        public void MakeStartCallFail()
+        {
+            shouldStartCallFail = true;
+        }
+
+        private void StartCallMaybeFail()
+        {
+            if (shouldStartCallFail)
+            {
+                throw new InvalidOperationException("Start call has failed.");
+            }
+        }
     }
 }

src/csharp/Grpc.Core/Channel.cs

@@ -136,7 +136,7 @@ namespace Grpc.Core
         /// </summary>
         public async Task WaitForStateChangedAsync(ChannelState lastObservedState, DateTime? deadline = null)
         {
-            var result = await WaitForStateChangedInternalAsync(lastObservedState, deadline).ConfigureAwait(false);
+            var result = await TryWaitForStateChangedAsync(lastObservedState, deadline).ConfigureAwait(false);
             if (!result)
             {
                 throw new TaskCanceledException("Reached deadline.");
@@ -147,7 +147,7 @@ namespace Grpc.Core
         /// Returned tasks completes once channel state has become different from
         /// given lastObservedState (<c>true</c> is returned) or if the wait has timed out (<c>false</c> is returned).
         /// </summary>
-        internal Task<bool> WaitForStateChangedInternalAsync(ChannelState lastObservedState, DateTime? deadline = null)
+        public Task<bool> TryWaitForStateChangedAsync(ChannelState lastObservedState, DateTime? deadline = null)
         {
             GrpcPreconditions.CheckArgument(lastObservedState != ChannelState.Shutdown,
                 "Shutdown is a terminal state. No further state changes can occur.");
@@ -297,6 +297,12 @@ namespace Grpc.Core
             activeCallCounter.Decrement();
         }
 
+        // for testing only
+        internal long GetCallReferenceCount()
+        {
+            return activeCallCounter.Count;
+        }
+
         private ChannelState GetConnectivityState(bool tryToConnect)
         {
             try

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -17,6 +17,7 @@
 #endregion
 
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 using Grpc.Core.Logging;
 using Grpc.Core.Profiling;
@@ -34,6 +35,8 @@ namespace Grpc.Core.Internal
         readonly CallInvocationDetails<TRequest, TResponse> details;
         readonly INativeCall injectedNativeCall;  // for testing
 
+        bool registeredWithChannel;
+
         // Dispose of to de-register cancellation token registration
         IDisposable cancellationTokenRegistration;
 
@@ -77,43 +80,59 @@ namespace Grpc.Core.Internal
             using (profiler.NewScope("AsyncCall.UnaryCall"))
             using (CompletionQueueSafeHandle cq = CompletionQueueSafeHandle.CreateSync())
             {
-                byte[] payload = UnsafeSerialize(msg);
+                bool callStartedOk = false;
+                try
+                {
+                    unaryResponseTcs = new TaskCompletionSource<TResponse>();
 
-                unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                    lock (myLock)
+                    {
+                        GrpcPreconditions.CheckState(!started);
+                        started = true;
+                        Initialize(cq);
 
-                lock (myLock)
-                {
-                    GrpcPreconditions.CheckState(!started);
-                    started = true;
-                    Initialize(cq);
+                        halfcloseRequested = true;
+                        readingDone = true;
+                    }
 
-                    halfcloseRequested = true;
-                    readingDone = true;
-                }
+                    byte[] payload = UnsafeSerialize(msg);
 
-                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
-                {
-                    var ctx = details.Channel.Environment.BatchContextPool.Lease();
-                    try
+                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                     {
-                        call.StartUnary(ctx, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
-                        var ev = cq.Pluck(ctx.Handle);
-                        bool success = (ev.success != 0);
+                        var ctx = details.Channel.Environment.BatchContextPool.Lease();
                         try
                         {
-                            using (profiler.NewScope("AsyncCall.UnaryCall.HandleBatch"))
+                            call.StartUnary(ctx, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                            callStartedOk = true;
+
+                            var ev = cq.Pluck(ctx.Handle);
+                            bool success = (ev.success != 0);
+                            try
+                            {
+                                using (profiler.NewScope("AsyncCall.UnaryCall.HandleBatch"))
+                                {
+                                    HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
+                                }
+                            }
+                            catch (Exception e)
                             {
-                                HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
+                                Logger.Error(e, "Exception occurred while invoking completion delegate.");
                             }
                         }
-                        catch (Exception e)
+                        finally
                         {
-                            Logger.Error(e, "Exception occurred while invoking completion delegate.");
+                            ctx.Recycle();
                         }
                     }
-                    finally
+                }
+                finally
+                {
+                    if (!callStartedOk)
                     {
-                        ctx.Recycle();
+                        lock (myLock)
+                        {
+                            OnFailedToStartCallLocked();
+                        }
                     }
                 }
                     
@@ -130,22 +149,35 @@ namespace Grpc.Core.Internal
         {
             lock (myLock)
             {
-                GrpcPreconditions.CheckState(!started);
-                started = true;
+                bool callStartedOk = false;
+                try
+                {
+                    GrpcPreconditions.CheckState(!started);
+                    started = true;
 
-                Initialize(details.Channel.CompletionQueue);
+                    Initialize(details.Channel.CompletionQueue);
 
-                halfcloseRequested = true;
-                readingDone = true;
+                    halfcloseRequested = true;
+                    readingDone = true;
+
+                    byte[] payload = UnsafeSerialize(msg);
 
-                byte[] payload = UnsafeSerialize(msg);
+                    unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    {
+                        call.StartUnary(UnaryResponseClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                        callStartedOk = true;
+                    }
 
-                unaryResponseTcs = new TaskCompletionSource<TResponse>();
-                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    return unaryResponseTcs.Task;
+                }
+                finally
                 {
-                    call.StartUnary(UnaryResponseClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                    if (!callStartedOk)
+                    {
+                        OnFailedToStartCallLocked();
+                    }
                 }
-                return unaryResponseTcs.Task;
             }
         }
 
@@ -157,20 +189,32 @@ namespace Grpc.Core.Internal
         {
             lock (myLock)
             {
-                GrpcPreconditions.CheckState(!started);
-                started = true;
+                bool callStartedOk = false;
+                try
+                {
+                    GrpcPreconditions.CheckState(!started);
+                    started = true;
 
-                Initialize(details.Channel.CompletionQueue);
+                    Initialize(details.Channel.CompletionQueue);
 
-                readingDone = true;
+                    readingDone = true;
+
+                    unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    {
+                        call.StartClientStreaming(UnaryResponseClientCallback, metadataArray, details.Options.Flags);
+                        callStartedOk = true;
+                    }
 
-                unaryResponseTcs = new TaskCompletionSource<TResponse>();
-                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    return unaryResponseTcs.Task;
+                }
+                finally
                 {
-                    call.StartClientStreaming(UnaryResponseClientCallback, metadataArray, details.Options.Flags);
+                    if (!callStartedOk)
+                    {
+                        OnFailedToStartCallLocked();
+                    }
                 }
-
-                return unaryResponseTcs.Task;
             }
         }
 
@@ -181,21 +225,33 @@ namespace Grpc.Core.Internal
         {
             lock (myLock)
             {
-                GrpcPreconditions.CheckState(!started);
-                started = true;
+                bool callStartedOk = false;
+                try
+                {
+                    GrpcPreconditions.CheckState(!started);
+                    started = true;
 
-                Initialize(details.Channel.CompletionQueue);
+                    Initialize(details.Channel.CompletionQueue);
 
-                halfcloseRequested = true;
+                    halfcloseRequested = true;
 
-                byte[] payload = UnsafeSerialize(msg);
+                    byte[] payload = UnsafeSerialize(msg);
 
-                streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
-                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
+                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    {
+                        call.StartServerStreaming(ReceivedStatusOnClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                        callStartedOk = true;
+                    }
+                    call.StartReceiveInitialMetadata(ReceivedResponseHeadersCallback);
+                }
+                finally
                 {
-                    call.StartServerStreaming(ReceivedStatusOnClientCallback, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
+                    if (!callStartedOk)
+                    {
+                        OnFailedToStartCallLocked();
+                    }
                 }
-                call.StartReceiveInitialMetadata(ReceivedResponseHeadersCallback);
             }
         }
 
@@ -207,17 +263,29 @@ namespace Grpc.Core.Internal
         {
             lock (myLock)
             {
-                GrpcPreconditions.CheckState(!started);
-                started = true;
+                bool callStartedOk = false;
+                try
+                {
+                    GrpcPreconditions.CheckState(!started);
+                    started = true;
 
-                Initialize(details.Channel.CompletionQueue);
+                    Initialize(details.Channel.CompletionQueue);
 
-                streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
-                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
+                    using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                    {
+                        call.StartDuplexStreaming(ReceivedStatusOnClientCallback, metadataArray, details.Options.Flags);
+                        callStartedOk = true;
+                    }
+                    call.StartReceiveInitialMetadata(ReceivedResponseHeadersCallback);
+                }
+                finally
                 {
-                    call.StartDuplexStreaming(ReceivedStatusOnClientCallback, metadataArray, details.Options.Flags);
+                    if (!callStartedOk)
+                    {
+                        OnFailedToStartCallLocked();
+                    }
                 }
-                call.StartReceiveInitialMetadata(ReceivedResponseHeadersCallback);
             }
         }
 
@@ -327,7 +395,11 @@ namespace Grpc.Core.Internal
 
         protected override void OnAfterReleaseResourcesLocked()
         {
-            details.Channel.RemoveCallReference(this);
+            if (registeredWithChannel)
+            {
+                details.Channel.RemoveCallReference(this);
+                registeredWithChannel = false;
+            }
         }
 
         protected override void OnAfterReleaseResourcesUnlocked()
@@ -394,10 +466,27 @@ namespace Grpc.Core.Internal
             var call = CreateNativeCall(cq);
 
             details.Channel.AddCallReference(this);
+            registeredWithChannel = true;
             InitializeInternal(call);
+
             RegisterCancellationCallback();
         }
 
+        private void OnFailedToStartCallLocked()
+        {
+            ReleaseResources();
+
+            // We need to execute the hook that disposes the cancellation token
+            // registration, but it cannot be done from under a lock.
+            // To make things simple, we just schedule the unregistering
+            // on a threadpool.
+            // - Once the native call is disposed, the Cancel() calls are ignored anyway
+            // - We don't care about the overhead as OnFailedToStartCallLocked() only happens
+            //   when something goes very bad when initializing a call and that should
+            //   never happen when gRPC is used correctly.
+            ThreadPool.QueueUserWorkItem((state) => OnAfterReleaseResourcesUnlocked());
+        }
+
         private INativeCall CreateNativeCall(CompletionQueueSafeHandle cq)
         {
             if (injectedNativeCall != null)

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

@@ -189,7 +189,7 @@ namespace Grpc.Core.Internal
         /// </summary>
         protected abstract Exception GetRpcExceptionClientOnly();
 
-        private void ReleaseResources()
+        protected void ReleaseResources()
         {
             if (call != null)
             {

src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs

@@ -68,8 +68,8 @@ namespace Grpc.Core.Internal
             }
             catch (Exception e)
             {
-                Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionStatusMsg);
-                Logger.Error(e, GetMetadataExceptionLogMsg);
+                // eat the exception, we must not throw when inside callback from native code.
+                Logger.Error(e, "Exception occurred while invoking native metadata interceptor handler.");
             }
         }
 
@@ -87,7 +87,8 @@ namespace Grpc.Core.Internal
             }
             catch (Exception e)
             {
-                Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionStatusMsg);
+                string detail = GetMetadataExceptionStatusMsg + " " + e.ToString();
+                Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, detail);
                 Logger.Error(e, GetMetadataExceptionLogMsg);
             }
         }

src/csharp/Grpc.Core/RpcException.cs

@@ -33,10 +33,8 @@ namespace Grpc.Core
         /// Creates a new <c>RpcException</c> associated with given status.
         /// </summary>
         /// <param name="status">Resulting status of a call.</param>
-        public RpcException(Status status) : base(status.ToString())
+        public RpcException(Status status) : this(status, Metadata.Empty, status.ToString())
         {
-            this.status = status;
-            this.trailers = Metadata.Empty;
         }
 
         /// <summary>
@@ -44,10 +42,8 @@ namespace Grpc.Core
         /// </summary>
         /// <param name="status">Resulting status of a call.</param>
         /// <param name="message">The exception message.</param> 
-        public RpcException(Status status, string message) : base(message)
+        public RpcException(Status status, string message) : this(status, Metadata.Empty, message)
         {
-            this.status = status;
-            this.trailers = Metadata.Empty;
         }
 
         /// <summary>
@@ -55,7 +51,17 @@ namespace Grpc.Core
         /// </summary>
         /// <param name="status">Resulting status of a call.</param>
         /// <param name="trailers">Response trailing metadata.</param> 
-        public RpcException(Status status, Metadata trailers) : base(status.ToString())
+        public RpcException(Status status, Metadata trailers) : this(status, trailers, status.ToString())
+        {
+        }
+
+        /// <summary>
+        /// Creates a new <c>RpcException</c> associated with given status, message and trailing response metadata.
+        /// </summary>
+        /// <param name="status">Resulting status of a call.</param>
+        /// <param name="trailers">Response trailing metadata.</param>
+        /// <param name="message">The exception message.</param>
+        public RpcException(Status status, Metadata trailers, string message) : base(message)
         {
             this.status = status;
             this.trailers = GrpcPreconditions.CheckNotNull(trailers);

src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs

@@ -153,9 +153,10 @@ namespace Grpc.IntegrationTesting
         [Test]
         public void MetadataCredentials_InterceptorThrows()
         {
+            var authInterceptorExceptionMessage = "Auth interceptor throws";
             var callCredentials = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) =>
             {
-                throw new Exception("Auth interceptor throws");
+                throw new Exception(authInterceptorExceptionMessage);
             }));
             var channelCredentials = ChannelCredentials.Create(TestCredentials.CreateSslCredentials(), callCredentials);
             channel = new Channel(Host, server.Ports.Single().BoundPort, channelCredentials, options);
@@ -163,6 +164,7 @@ namespace Grpc.IntegrationTesting
 
             var ex = Assert.Throws<RpcException>(() => client.UnaryCall(new SimpleRequest { }));
             Assert.AreEqual(StatusCode.Unavailable, ex.Status.StatusCode);
+            StringAssert.Contains(authInterceptorExceptionMessage, ex.Status.Detail);
         }
 
         private class FakeTestService : TestService.TestServiceBase

src/python/grpcio/grpc/BUILD.bazel

@@ -2,7 +2,7 @@ load("@grpc_python_dependencies//:requirements.bzl", "requirement")
 
 package(default_visibility = ["//visibility:public"])
 
-py_binary(
+py_library(
     name = "grpcio",
     srcs = ["__init__.py"],
     deps = [
@@ -22,7 +22,6 @@ py_binary(
     data = [
         "//:grpc",
     ],
-    main = "__init__.py",
     imports = ["../",],
 )
 

src/python/grpcio/grpc/_channel.py

@@ -24,6 +24,7 @@ from grpc import _grpcio_metadata
 from grpc._cython import cygrpc
 from grpc.framework.foundation import callable_util
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 _USER_AGENT = 'grpc-python/{}'.format(_grpcio_metadata.__version__)

src/python/grpcio/grpc/_common.py

@@ -20,6 +20,7 @@ import six
 import grpc
 from grpc._cython import cygrpc
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 CYGRPC_CONNECTIVITY_STATE_TO_CHANNEL_CONNECTIVITY = {

src/python/grpcio/grpc/_cython/BUILD.bazel

@@ -8,6 +8,7 @@ pyx_library(
         "__init__.py",
         "cygrpc.pxd",
         "cygrpc.pyx",
+        "_cygrpc/_hooks.pyx.pxi",
         "_cygrpc/grpc_string.pyx.pxi",
         "_cygrpc/arguments.pyx.pxi",
         "_cygrpc/call.pyx.pxi",
@@ -15,6 +16,7 @@ pyx_library(
         "_cygrpc/credentials.pyx.pxi",
         "_cygrpc/completion_queue.pyx.pxi",
         "_cygrpc/event.pyx.pxi",
+        "_cygrpc/fork_posix.pyx.pxi",
         "_cygrpc/metadata.pyx.pxi",
         "_cygrpc/operation.pyx.pxi",
         "_cygrpc/records.pyx.pxi",
@@ -24,12 +26,14 @@ pyx_library(
         "_cygrpc/time.pyx.pxi",
         "_cygrpc/grpc_gevent.pyx.pxi",
         "_cygrpc/grpc.pxi",
+        "_cygrpc/_hooks.pxd.pxi",
         "_cygrpc/arguments.pxd.pxi",
         "_cygrpc/call.pxd.pxi",
         "_cygrpc/channel.pxd.pxi",
         "_cygrpc/credentials.pxd.pxi",
         "_cygrpc/completion_queue.pxd.pxi",
         "_cygrpc/event.pxd.pxi",
+        "_cygrpc/fork_posix.pxd.pxi",
         "_cygrpc/metadata.pxd.pxi",
         "_cygrpc/operation.pxd.pxi",
         "_cygrpc/records.pxd.pxi",

src/python/grpcio/grpc/_cython/_cygrpc/grpc_string.pyx.pxi

@@ -14,6 +14,7 @@
 
 import logging
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 # This function will ascii encode unicode string inputs if neccesary.

src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi

@@ -18,6 +18,7 @@ import logging
 import time
 import grpc
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 cdef class Server:

src/python/grpcio/grpc/_plugin_wrapping.py

@@ -20,6 +20,7 @@ import grpc
 from grpc import _common
 from grpc._cython import cygrpc
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio/grpc/_server.py

@@ -27,6 +27,7 @@ from grpc import _interceptor
 from grpc._cython import cygrpc
 from grpc.framework.foundation import callable_util
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 _SHUTDOWN_TAG = 'shutdown'

src/python/grpcio/grpc/framework/foundation/callable_util.py

@@ -21,6 +21,7 @@ import logging
 
 import six
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio/grpc/framework/foundation/logging_pool.py

@@ -17,6 +17,7 @@ import logging
 
 from concurrent import futures
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio/grpc/framework/foundation/stream_util.py

@@ -19,6 +19,7 @@ import threading
 from grpc.framework.foundation import stream
 
 _NO_VALUE = object()
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio_testing/grpc_testing/_channel/_invocation.py

@@ -18,6 +18,7 @@ import threading
 import grpc
 
 _NOT_YET_OBSERVED = object()
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio_testing/grpc_testing/_server/_rpc.py

@@ -18,6 +18,7 @@ import threading
 import grpc
 from grpc_testing import _common
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio_testing/grpc_testing/_time.py

@@ -21,6 +21,7 @@ import time as _time
 import grpc
 import grpc_testing
 
+logging.basicConfig()
 _LOGGER = logging.getLogger(__name__)
 
 

src/python/grpcio_tests/tests/interop/server.py

@@ -25,6 +25,7 @@ from tests.interop import methods
 from tests.interop import resources
 from tests.unit import test_common
 
+logging.basicConfig()
 _ONE_DAY_IN_SECONDS = 60 * 60 * 24
 _LOGGER = logging.getLogger(__name__)
 

templates/tools/dockerfile/interoptest/grpc_interop_dart/Dockerfile.template

@@ -14,7 +14,7 @@
   # See the License for the specific language governing permissions and
   # limitations under the License.
 
-  FROM google/dart:latest
+  FROM google/dart:2.0
 
   # Upgrade Dart to version 2.
   RUN apt-get update && apt-get upgrade -y dart

test/core/channel/channel_trace_test.cc

@@ -44,8 +44,8 @@ namespace testing {
 // testing peer to access channel internals
 class ChannelNodePeer {
  public:
-  ChannelNodePeer(ChannelNode* node) : node_(node) {}
-  ChannelTrace* trace() { return &node_->trace_; }
+  explicit ChannelNodePeer(ChannelNode* node) : node_(node) {}
+  ChannelTrace* trace() const { return &node_->trace_; }
 
  private:
   ChannelNode* node_;

test/core/channel/channelz_test.cc

@@ -47,8 +47,8 @@ namespace testing {
 // testing peer to access channel internals
 class CallCountingHelperPeer {
  public:
-  CallCountingHelperPeer(CallCountingHelper* node) : node_(node) {}
-  grpc_millis last_call_started_millis() {
+  explicit CallCountingHelperPeer(CallCountingHelper* node) : node_(node) {}
+  grpc_millis last_call_started_millis() const {
     return (grpc_millis)gpr_atm_no_barrier_load(
         &node_->last_call_started_millis_);
   }
@@ -146,20 +146,21 @@ class ChannelFixture {
 
 class ServerFixture {
  public:
-  ServerFixture(int max_trace_nodes = 0) {
-    grpc_arg server_a[2];
-    server_a[0] = grpc_channel_arg_integer_create(
-        const_cast<char*>(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE),
-        max_trace_nodes);
-    server_a[1] = grpc_channel_arg_integer_create(
-        const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ), true);
+  explicit ServerFixture(int max_trace_nodes = 0) {
+    grpc_arg server_a[] = {
+        grpc_channel_arg_integer_create(
+            const_cast<char*>(GRPC_ARG_MAX_CHANNEL_TRACE_EVENTS_PER_NODE),
+            max_trace_nodes),
+        grpc_channel_arg_integer_create(
+            const_cast<char*>(GRPC_ARG_ENABLE_CHANNELZ), true),
+    };
     grpc_channel_args server_args = {GPR_ARRAY_SIZE(server_a), server_a};
     server_ = grpc_server_create(&server_args, nullptr);
   }
 
   ~ServerFixture() { grpc_server_destroy(server_); }
 
-  grpc_server* server() { return server_; }
+  grpc_server* server() const { return server_; }
 
  private:
   grpc_server* server_;

test/core/client_channel/parse_address_test.cc

@@ -91,6 +91,15 @@ static void test_grpc_parse_ipv6(const char* uri_text, const char* host,
   grpc_uri_destroy(uri);
 }
 
+/* Test parsing invalid ipv6 addresses (valid uri_text but invalid ipv6 addr) */
+static void test_grpc_parse_ipv6_invalid(const char* uri_text) {
+  grpc_core::ExecCtx exec_ctx;
+  grpc_uri* uri = grpc_uri_parse(uri_text, 0);
+  grpc_resolved_address addr;
+  GPR_ASSERT(!grpc_parse_ipv6(uri, &addr));
+  grpc_uri_destroy(uri);
+}
+
 int main(int argc, char** argv) {
   grpc_test_init(argc, argv);
   grpc_init();
@@ -100,5 +109,10 @@ int main(int argc, char** argv) {
   test_grpc_parse_ipv6("ipv6:[2001:db8::1]:12345", "2001:db8::1", 12345, 0);
   test_grpc_parse_ipv6("ipv6:[2001:db8::1%252]:12345", "2001:db8::1", 12345, 2);
 
+  /* Address length greater than GRPC_INET6_ADDRSTRLEN */
+  test_grpc_parse_ipv6_invalid(
+      "ipv6:WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW45%"
+      "v6:45%x$1*");
+
   grpc_shutdown();
 }

test/core/end2end/fixtures/http_proxy_fixture.cc

@@ -52,6 +52,16 @@
 #include "test/core/util/port.h"
 
 struct grpc_end2end_http_proxy {
+  grpc_end2end_http_proxy()
+      : proxy_name(nullptr),
+        server(nullptr),
+        channel_args(nullptr),
+        mu(nullptr),
+        pollset(nullptr),
+        combiner(nullptr) {
+    gpr_ref_init(&users, 1);
+    combiner = grpc_combiner_create();
+  }
   char* proxy_name;
   grpc_core::Thread thd;
   grpc_tcp_server* server;
@@ -519,11 +529,7 @@ static void thread_main(void* arg) {
 grpc_end2end_http_proxy* grpc_end2end_http_proxy_create(
     grpc_channel_args* args) {
   grpc_core::ExecCtx exec_ctx;
-  grpc_end2end_http_proxy* proxy =
-      static_cast<grpc_end2end_http_proxy*>(gpr_malloc(sizeof(*proxy)));
-  memset(proxy, 0, sizeof(*proxy));
-  proxy->combiner = grpc_combiner_create();
-  gpr_ref_init(&proxy->users, 1);
+  grpc_end2end_http_proxy* proxy = grpc_core::New<grpc_end2end_http_proxy>();
   // Construct proxy address.
   const int proxy_port = grpc_pick_unused_port_or_die();
   gpr_join_host_port(&proxy->proxy_name, "localhost", proxy_port);
@@ -573,7 +579,7 @@ void grpc_end2end_http_proxy_destroy(grpc_end2end_http_proxy* proxy) {
                         GRPC_CLOSURE_CREATE(destroy_pollset, proxy->pollset,
                                             grpc_schedule_on_exec_ctx));
   GRPC_COMBINER_UNREF(proxy->combiner, "test");
-  gpr_free(proxy);
+  grpc_core::Delete(proxy);
 }
 
 const char* grpc_end2end_http_proxy_get_proxy_name(

test/core/end2end/fixtures/proxy.cc

@@ -30,6 +30,17 @@
 #include "test/core/util/port.h"
 
 struct grpc_end2end_proxy {
+  grpc_end2end_proxy()
+      : proxy_port(nullptr),
+        server_port(nullptr),
+        cq(nullptr),
+        server(nullptr),
+        client(nullptr),
+        shutdown(false),
+        new_call(nullptr) {
+    memset(&new_call_details, 0, sizeof(new_call_details));
+    memset(&new_call_metadata, 0, sizeof(new_call_metadata));
+  }
   grpc_core::Thread thd;
   char* proxy_port;
   char* server_port;
@@ -79,9 +90,7 @@ grpc_end2end_proxy* grpc_end2end_proxy_create(const grpc_end2end_proxy_def* def,
   int proxy_port = grpc_pick_unused_port_or_die();
   int server_port = grpc_pick_unused_port_or_die();
 
-  grpc_end2end_proxy* proxy =
-      static_cast<grpc_end2end_proxy*>(gpr_malloc(sizeof(*proxy)));
-  memset(proxy, 0, sizeof(*proxy));
+  grpc_end2end_proxy* proxy = grpc_core::New<grpc_end2end_proxy>();
 
   gpr_join_host_port(&proxy->proxy_port, "localhost", proxy_port);
   gpr_join_host_port(&proxy->server_port, "localhost", server_port);
@@ -128,7 +137,7 @@ void grpc_end2end_proxy_destroy(grpc_end2end_proxy* proxy) {
   grpc_channel_destroy(proxy->client);
   grpc_completion_queue_destroy(proxy->cq);
   grpc_call_details_destroy(&proxy->new_call_details);
-  gpr_free(proxy);
+  grpc_core::Delete(proxy);
 }
 
 static void unrefpc(proxy_call* pc, const char* reason) {

test/core/end2end/tests/channelz.cc

@@ -240,7 +240,7 @@ static void test_channelz(grpc_end2end_test_config config) {
   GPR_ASSERT(nullptr != strstr(json, "\"callsStarted\":\"2\""));
   GPR_ASSERT(nullptr != strstr(json, "\"callsFailed\":\"1\""));
   GPR_ASSERT(nullptr != strstr(json, "\"callsSucceeded\":\"1\""));
-  // channel tracing is not enables, so these should not be preset.
+  // channel tracing is not enabled, so these should not be preset.
   GPR_ASSERT(nullptr == strstr(json, "\"trace\""));
   GPR_ASSERT(nullptr == strstr(json, "\"description\":\"Channel created\""));
   GPR_ASSERT(nullptr == strstr(json, "\"severity\":\"CT_INFO\""));
@@ -252,7 +252,7 @@ static void test_channelz(grpc_end2end_test_config config) {
   GPR_ASSERT(nullptr != strstr(json, "\"callsStarted\":\"2\""));
   GPR_ASSERT(nullptr != strstr(json, "\"callsFailed\":\"1\""));
   GPR_ASSERT(nullptr != strstr(json, "\"callsSucceeded\":\"1\""));
-  // channel tracing is not enables, so these should not be preset.
+  // channel tracing is not enabled, so these should not be preset.
   GPR_ASSERT(nullptr == strstr(json, "\"trace\""));
   GPR_ASSERT(nullptr == strstr(json, "\"description\":\"Channel created\""));
   GPR_ASSERT(nullptr == strstr(json, "\"severity\":\"CT_INFO\""));

test/core/end2end/tests/filter_status_code.cc

@@ -16,6 +16,14 @@
  *
  */
 
+/* This test verifies -
+ * 1) grpc_call_final_info passed to the filters on destroying a call contains
+ * the proper status.
+ * 2) If the response has both an HTTP status code and a gRPC status code, then
+ * we should prefer the gRPC status code as mentioned in
+ * https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md
+ */
+
 #include "test/core/end2end/end2end_tests.h"
 
 #include <limits.h>
@@ -249,6 +257,22 @@ typedef struct final_status_data {
   grpc_call_stack* call;
 } final_status_data;
 
+static void server_start_transport_stream_op_batch(
+    grpc_call_element* elem, grpc_transport_stream_op_batch* op) {
+  auto* data = static_cast<final_status_data*>(elem->call_data);
+  if (data->call == g_server_call_stack) {
+    if (op->send_initial_metadata) {
+      auto* batch = op->payload->send_initial_metadata.send_initial_metadata;
+      if (batch->idx.named.status != nullptr) {
+        /* Replace the HTTP status with 404 */
+        grpc_metadata_batch_substitute(batch, batch->idx.named.status,
+                                       GRPC_MDELEM_STATUS_404);
+      }
+    }
+  }
+  grpc_call_next_op(elem, op);
+}
+
 static grpc_error* init_call_elem(grpc_call_element* elem,
                                   const grpc_call_element_args* args) {
   final_status_data* data = static_cast<final_status_data*>(elem->call_data);
@@ -307,7 +331,7 @@ static const grpc_channel_filter test_client_filter = {
     "client_filter_status_code"};
 
 static const grpc_channel_filter test_server_filter = {
-    grpc_call_next_op,
+    server_start_transport_stream_op_batch,
     grpc_channel_next_op,
     sizeof(final_status_data),
     init_call_elem,

test/core/iomgr/error_test.cc

@@ -187,16 +187,6 @@ static void test_os_error() {
   GRPC_ERROR_UNREF(error);
 }
 
-static void test_special() {
-  grpc_error* error = GRPC_ERROR_NONE;
-  error = grpc_error_add_child(
-      error, GRPC_ERROR_CREATE_FROM_STATIC_STRING("test child"));
-  intptr_t i;
-  GPR_ASSERT(grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, &i));
-  GPR_ASSERT(i == GRPC_STATUS_OK);
-  GRPC_ERROR_UNREF(error);
-}
-
 static void test_overflow() {
   grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Overflow");
 
@@ -235,7 +225,6 @@ int main(int argc, char** argv) {
   test_os_error();
   test_create_referencing();
   test_create_referencing_many();
-  test_special();
   test_overflow();
   grpc_shutdown();
 

test/core/iomgr/timer_list_test.cc

@@ -248,11 +248,7 @@ int main(int argc, char** argv) {
     grpc_determine_iomgr_platform();
     grpc_iomgr_platform_init();
     gpr_set_log_verbosity(GPR_LOG_SEVERITY_DEBUG);
-#ifndef GPR_WINDOWS
-    /* Skip this test on Windows until we figure out why it fails */
-    /* https://github.com/grpc/grpc/issues/16417 */
     long_running_service_cleanup_test();
-#endif  // GPR_WINDOWS
     add_test();
     destruction_test();
     grpc_iomgr_platform_shutdown();

test/core/security/linux_system_roots_test.cc

@@ -41,10 +41,6 @@
 
 #include "gtest/gtest.h"
 
-#ifndef GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR
-#define GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR "GRPC_USE_SYSTEM_SSL_ROOTS"
-#endif
-
 namespace grpc {
 namespace {
 
@@ -68,7 +64,6 @@ TEST(CreateRootCertsBundleTest, ReturnsEmpty) {
 }
 
 TEST(CreateRootCertsBundleTest, BundlesCorrectly) {
-  gpr_setenv(GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR, "true");
   // Test that CreateRootCertsBundle returns a correct slice.
   grpc_slice roots_bundle = grpc_empty_slice();
   GRPC_LOG_IF_ERROR(
@@ -81,7 +76,6 @@ TEST(CreateRootCertsBundleTest, BundlesCorrectly) {
   char* bundle_str = grpc_slice_to_c_string(roots_bundle);
   EXPECT_STREQ(result_str, bundle_str);
   // Clean up.
-  unsetenv(GRPC_USE_SYSTEM_SSL_ROOTS_ENV_VAR);
   gpr_free(result_str);
   gpr_free(bundle_str);
   grpc_slice_unref(roots_bundle);

test/core/security/security_connector_test.cc

@@ -415,6 +415,7 @@ static void test_default_ssl_roots(void) {
 
   /* Now setup a permanent failure for the overridden roots and we should get
      an empty slice. */
+  gpr_setenv("GRPC_NOT_USE_SYSTEM_SSL_ROOTS", "true");
   grpc_set_ssl_roots_override_callback(override_roots_permanent_failure);
   roots = grpc_core::TestDefaultSslRootStore::ComputePemRootCertsForTesting();
   GPR_ASSERT(GRPC_SLICE_IS_EMPTY(roots));

test/core/util/port_isolated_runtime_environment.cc

@@ -16,9 +16,12 @@
  *
  */
 
-/* When running tests on remote machines, the framework takes a round-robin pick
- * of a port within certain range. There is no need to recycle ports.
+/* When individual tests run in an isolated runtime environment (e.g. each test
+ * runs in a separate container) the framework takes a round-robin pick of a
+ * port within certain range. There is no need to recycle ports.
  */
+#include <grpc/support/atm.h>
+#include <grpc/support/log.h>
 #include <grpc/support/time.h>
 #include <stdlib.h>
 #include "src/core/lib/iomgr/port.h"
@@ -28,22 +31,24 @@
 #include "test/core/util/port.h"
 
 #define MIN_PORT 49152
-#define MAX_PORT 65536
+#define MAX_PORT 65535
 
-int get_random_starting_port() {
+static int get_random_port_offset() {
   srand(gpr_now(GPR_CLOCK_REALTIME).tv_nsec);
-  return rand() % (MAX_PORT - MIN_PORT + 1) + MIN_PORT;
+  double rnd = static_cast<double>(rand()) /
+               (static_cast<double>(RAND_MAX) + 1.0);  // values from [0,1)
+  return static_cast<int>(rnd * (MAX_PORT - MIN_PORT + 1));
 }
 
-static int s_allocated_port = get_random_starting_port();
+static int s_initial_offset = get_random_port_offset();
+static gpr_atm s_pick_counter = 0;
 
 int grpc_pick_unused_port_or_die(void) {
-  int allocated_port = s_allocated_port++;
-  if (s_allocated_port == MAX_PORT) {
-    s_allocated_port = MIN_PORT;
-  }
-
-  return allocated_port;
+  int orig_counter_val =
+      static_cast<int>(gpr_atm_full_fetch_add(&s_pick_counter, 1));
+  GPR_ASSERT(orig_counter_val < (MAX_PORT - MIN_PORT + 1));
+  return MIN_PORT +
+         (s_initial_offset + orig_counter_val) % (MAX_PORT - MIN_PORT + 1);
 }
 
 void grpc_recycle_unused_port(int port) { (void)port; }

test/cpp/end2end/channelz_service_test.cc

@@ -375,7 +375,6 @@ TEST_F(ChannelzServerTest, ManySubchannels) {
     SendFailedEcho(1);
     SendFailedEcho(2);
   }
-
   GetTopChannelsRequest gtc_request;
   GetTopChannelsResponse gtc_response;
   gtc_request.set_start_channel_id(0);
@@ -384,11 +383,6 @@ TEST_F(ChannelzServerTest, ManySubchannels) {
       channelz_stub_->GetTopChannels(&context, gtc_request, &gtc_response);
   EXPECT_TRUE(s.ok()) << s.error_message();
   EXPECT_EQ(gtc_response.channel_size(), kNumChannels);
-
-  // std::string gtc_str;
-  // google::protobuf::TextFormat::PrintToString(gtc_response, &gtc_str);
-  // std::cout << "GetTopChannels:\n" << gtc_str << "\n";
-
   for (int i = 0; i < gtc_response.channel_size(); ++i) {
     // if the channel sent no RPCs, then expect no subchannels to have been
     // created.
@@ -396,8 +390,7 @@ TEST_F(ChannelzServerTest, ManySubchannels) {
       EXPECT_EQ(gtc_response.channel(i).subchannel_ref_size(), 0);
       continue;
     }
-    // Since this is pick first, we know that there was only one subchannel
-    // used. We request it here.
+    // The resolver must return at least one address.
     ASSERT_GT(gtc_response.channel(i).subchannel_ref_size(), 0);
     GetSubchannelRequest gsc_request;
     GetSubchannelResponse gsc_response;

test/cpp/qps/BUILD

@@ -15,6 +15,7 @@
 licenses(["notice"])  # Apache v2
 
 load("//bazel:grpc_build_system.bzl", "grpc_cc_test", "grpc_cc_library", "grpc_cc_binary", "grpc_package")
+load("//test/cpp/qps:qps_benchmark_script.bzl", "qps_json_driver_batch", "json_run_localhost_batch")
 
 grpc_package(name = "test/cpp/qps")
 
@@ -22,8 +23,8 @@ grpc_cc_library(
     name = "parse_json",
     srcs = ["parse_json.cc"],
     hdrs = ["parse_json.h"],
-    deps = ["//:grpc++"],
     external_deps = ["protobuf"],
+    deps = ["//:grpc++"],
 )
 
 grpc_cc_library(
@@ -31,16 +32,19 @@ grpc_cc_library(
     srcs = [
         "client_async.cc",
         "client_sync.cc",
+        "qps_server_builder.cc",
         "qps_worker.cc",
         "server_async.cc",
         "server_sync.cc",
-        "qps_server_builder.cc",
     ],
     hdrs = [
         "client.h",
+        "qps_server_builder.h",
         "qps_worker.h",
         "server.h",
-        "qps_server_builder.h",
+    ],
+    external_deps = [
+        "gflags",
     ],
     deps = [
         ":histogram",
@@ -56,11 +60,8 @@ grpc_cc_library(
         "//test/core/end2end:ssl_test_data",
         "//test/core/util:gpr_test_util",
         "//test/core/util:grpc_test_util",
-        "//test/cpp/util:test_util",
         "//test/cpp/util:test_config",
-    ],
-    external_deps = [
-        "gflags",
+        "//test/cpp/util:test_util",
     ],
 )
 
@@ -97,15 +98,15 @@ grpc_cc_library(
     hdrs = [
         "benchmark_config.h",
     ],
+    external_deps = [
+        "gflags",
+    ],
     deps = [
         ":driver_impl",
         ":histogram",
         "//:grpc++",
         "//src/proto/grpc/testing:control_proto",
     ],
-    external_deps = [
-        "gflags",
-    ],
 )
 
 grpc_cc_library(
@@ -117,6 +118,21 @@ grpc_cc_library(
     deps = ["//test/core/util:grpc_test_util"],
 )
 
+grpc_cc_binary(
+    name = "qps_json_driver",
+    srcs = ["qps_json_driver.cc"],
+    external_deps = [
+        "gflags",
+    ],
+    deps = [
+        ":benchmark_config",
+        ":driver_impl",
+        "//:grpc++",
+        "//test/cpp/util:test_config",
+        "//test/cpp/util:test_util",
+    ],
+)
+
 grpc_cc_test(
     name = "inproc_sync_unary_ping_pong_test",
     srcs = ["inproc_sync_unary_ping_pong_test.cc"],
@@ -135,17 +151,9 @@ grpc_cc_library(
     deps = ["//:grpc++"],
 )
 
-grpc_cc_binary(
-    name = "json_run_localhost",
-    srcs = ["json_run_localhost.cc"],
-    deps = [
-        "//:gpr",
-        "//test/core/util:gpr_test_util",
-        "//test/core/util:grpc_test_util",
-        "//test/cpp/util:test_config",
-        "//test/cpp/util:test_util",
-    ],
-)
+qps_json_driver_batch()
+
+json_run_localhost_batch()
 
 grpc_cc_test(
     name = "qps_interarrival_test",
@@ -157,24 +165,10 @@ grpc_cc_test(
     ],
 )
 
-grpc_cc_binary(
-    name = "qps_json_driver",
-    srcs = ["qps_json_driver.cc"],
-    deps = [
-        ":benchmark_config",
-        ":driver_impl",
-        "//:grpc++",
-        "//test/cpp/util:test_config",
-        "//test/cpp/util:test_util",
-    ],
-    external_deps = [
-        "gflags",
-    ],
-)
-
 grpc_cc_test(
     name = "qps_openloop_test",
     srcs = ["qps_openloop_test.cc"],
+    data = ["//third_party/toolchains:RBE_USE_MACHINE_TYPE_LARGE"],
     deps = [
         ":benchmark_config",
         ":driver_impl",
@@ -182,7 +176,6 @@ grpc_cc_test(
         "//test/cpp/util:test_config",
         "//test/cpp/util:test_util",
     ],
-    data = ["//third_party/toolchains:RBE_USE_MACHINE_TYPE_LARGE"],
 )
 
 grpc_cc_test(

test/cpp/qps/gen_build_yaml.py

@@ -14,6 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
 import json
 import pipes
 import shutil
@@ -68,62 +69,66 @@ def maybe_exclude_gcov(scenario_json):
     return ['gcov']
   return []
 
-print yaml.dump({
-  'tests': [
-    {
-      'name': 'json_run_localhost',
-      'shortname': 'json_run_localhost:%s' % scenario_json['name'],
-      'args': ['--scenarios_json', _scenario_json_string(scenario_json, False)],
-      'ci_platforms': ['linux'],
-      'platforms': ['linux'],
-      'flaky': False,
-      'language': 'c++',
-      'boringssl': True,
-      'defaults': 'boringssl',
-      'cpu_cost': guess_cpu(scenario_json, False),
-      'exclude_configs': ['tsan', 'asan'] + maybe_exclude_gcov(scenario_json),
-      'timeout_seconds': 2*60,
-      'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', []),
-      'auto_timeout_scaling': False
-    }
-    for scenario_json in scenario_config.CXXLanguage().scenarios()
-    if 'scalable' in scenario_json.get('CATEGORIES', [])
-  ] + [
-    {
-      'name': 'qps_json_driver',
-      'shortname': 'qps_json_driver:inproc_%s' % scenario_json['name'],
-      'args': ['--run_inproc', '--scenarios_json', _scenario_json_string(scenario_json, False)],
-      'ci_platforms': ['linux'],
-      'platforms': ['linux'],
-      'flaky': False,
-      'language': 'c++',
-      'boringssl': True,
-      'defaults': 'boringssl',
-      'cpu_cost': guess_cpu(scenario_json, False),
-      'exclude_configs': ['tsan', 'asan'],
-      'timeout_seconds': 6*60,
-      'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', [])
-    }
-    for scenario_json in scenario_config.CXXLanguage().scenarios()
-    if 'inproc' in scenario_json.get('CATEGORIES', [])
-  ] + [
-    {
-      'name': 'json_run_localhost',
-      'shortname': 'json_run_localhost:%s_low_thread_count' % scenario_json['name'],
-      'args': ['--scenarios_json', _scenario_json_string(scenario_json, True)],
-      'ci_platforms': ['linux'],
-      'platforms': ['linux'],
-      'flaky': False,
-      'language': 'c++',
-      'boringssl': True,
-      'defaults': 'boringssl',
-      'cpu_cost': guess_cpu(scenario_json, True),
-      'exclude_configs': sorted(c for c in configs_from_yaml if c not in ('tsan', 'asan')),
-      'timeout_seconds': 10*60,
-      'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', []),
-      'auto_timeout_scaling': False
-   }
-    for scenario_json in scenario_config.CXXLanguage().scenarios()
-    if 'scalable' in scenario_json.get('CATEGORIES', [])
-  ]
-})
+def generate_yaml():
+  return {
+    'tests': [
+      {
+        'name': 'json_run_localhost',
+        'shortname': 'json_run_localhost:%s' % scenario_json['name'],
+        'args': ['--scenarios_json', _scenario_json_string(scenario_json, False)],
+        'ci_platforms': ['linux'],
+        'platforms': ['linux'],
+        'flaky': False,
+        'language': 'c++',
+        'boringssl': True,
+        'defaults': 'boringssl',
+        'cpu_cost': guess_cpu(scenario_json, False),
+        'exclude_configs': ['tsan', 'asan'] + maybe_exclude_gcov(scenario_json),
+        'timeout_seconds': 2*60,
+        'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', []),
+        'auto_timeout_scaling': False
+      }
+      for scenario_json in scenario_config.CXXLanguage().scenarios()
+      if 'scalable' in scenario_json.get('CATEGORIES', [])
+    ] + [
+      {
+        'name': 'qps_json_driver',
+        'shortname': 'qps_json_driver:inproc_%s' % scenario_json['name'],
+        'args': ['--run_inproc', '--scenarios_json', _scenario_json_string(scenario_json, False)],
+        'ci_platforms': ['linux'],
+        'platforms': ['linux'],
+        'flaky': False,
+        'language': 'c++',
+        'boringssl': True,
+        'defaults': 'boringssl',
+        'cpu_cost': guess_cpu(scenario_json, False),
+        'exclude_configs': ['tsan', 'asan'],
+        'timeout_seconds': 6*60,
+        'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', [])
+      }
+      for scenario_json in scenario_config.CXXLanguage().scenarios()
+      if 'inproc' in scenario_json.get('CATEGORIES', [])
+    ] + [
+      {
+        'name': 'json_run_localhost',
+        'shortname': 'json_run_localhost:%s_low_thread_count' % scenario_json['name'],
+        'args': ['--scenarios_json', _scenario_json_string(scenario_json, True)],
+        'ci_platforms': ['linux'],
+        'platforms': ['linux'],
+        'flaky': False,
+        'language': 'c++',
+        'boringssl': True,
+        'defaults': 'boringssl',
+        'cpu_cost': guess_cpu(scenario_json, True),
+        'exclude_configs': sorted(c for c in configs_from_yaml if c not in ('tsan', 'asan')),
+        'timeout_seconds': 10*60,
+        'excluded_poll_engines': scenario_json.get('EXCLUDED_POLL_ENGINES', []),
+        'auto_timeout_scaling': False
+     }
+      for scenario_json in scenario_config.CXXLanguage().scenarios()
+      if 'scalable' in scenario_json.get('CATEGORIES', [])
+    ]
+  }
+
+
+print(yaml.dump(generate_yaml()))

test/cpp/qps/json_run_localhost_scenario_gen.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python2.7
+
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import gen_build_yaml as gen
+import json
+
+def generate_args():
+    all_scenario_set = gen.generate_yaml()
+    all_scenario_set = all_scenario_set['tests']
+    json_run_localhost_scenarios = \
+        [item for item in all_scenario_set if item['name'] == 'json_run_localhost']
+    json_run_localhost_arg_set = \
+        [item['args'][1] for item in json_run_localhost_scenarios \
+        if 'args' in item and len(item['args']) > 1]
+    deserialized_scenarios = [json.loads(item)['scenarios'][0] \
+                              for item in json_run_localhost_arg_set]
+    all_scenarios = {scenario['name'].encode('ascii', 'ignore'): \
+                    '\'{\'scenarios\' : [' + json.dumps(scenario) + ']}\'' \
+                    for scenario in deserialized_scenarios}
+
+    serialized_scenarios_str = str(all_scenarios).encode('ascii', 'ignore')
+    with open('json_run_localhost_scenarios.bzl', 'wb') as f:
+        f.write('"""Scenarios run on localhost."""\n\n')
+        f.write('JSON_RUN_LOCALHOST_SCENARIOS = ' + serialized_scenarios_str + '\n')
+
+generate_args()

test/cpp/qps/qps_benchmark_script.bzl

@@ -0,0 +1,80 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#
+# This is for the gRPC build system. This isn't intended to be used outsite of
+# the BUILD file for gRPC. It contains the mapping for the template system we
+# use to generate other platform's build system files.
+#
+# Please consider that there should be a high bar for additions and changes to
+# this file.
+# Each rule listed must be re-written for Google's internal build system, and
+# each change must be ported from one to the other.
+#
+
+"""Script to run qps benchmark."""
+
+load("//bazel:grpc_build_system.bzl", "grpc_cc_test")
+load("//test/cpp/qps:qps_json_driver_scenarios.bzl", "QPS_JSON_DRIVER_SCENARIOS")
+load("//test/cpp/qps:json_run_localhost_scenarios.bzl", "JSON_RUN_LOCALHOST_SCENARIOS")
+
+def qps_json_driver_batch():
+    for scenario in QPS_JSON_DRIVER_SCENARIOS:
+        grpc_cc_test(
+            name = "qps_json_driver_test_%s" % scenario,
+            srcs = ["qps_json_driver.cc"],
+            args = [
+                "--run_inproc",
+                "--scenarios_json",
+                QPS_JSON_DRIVER_SCENARIOS[scenario],
+            ],
+            external_deps = [
+                "gflags",
+            ],
+            deps = [
+                ":benchmark_config",
+                ":driver_impl",
+                "//:grpc++",
+                "//test/cpp/util:test_config",
+                "//test/cpp/util:test_util",
+            ],
+            tags = [
+                "qps_json_driver",
+            ],
+        )
+
+def json_run_localhost_batch():
+    for scenario in JSON_RUN_LOCALHOST_SCENARIOS:
+        grpc_cc_test(
+            name = "json_run_localhost_%s" % scenario,
+            srcs = ["json_run_localhost.cc"],
+            args = [
+                "--scenarios_json",
+                JSON_RUN_LOCALHOST_SCENARIOS[scenario],
+            ],
+            data = [
+                "//test/cpp/qps:qps_json_driver",
+                "//test/cpp/qps:qps_worker",
+            ],
+            deps = [
+                "//:gpr",
+                "//test/core/util:gpr_test_util",
+                "//test/core/util:grpc_test_util",
+                "//test/cpp/util:test_config",
+                "//test/cpp/util:test_util",
+            ],
+            tags = [
+                "json_run_localhost",
+            ],
+        )

test/cpp/qps/qps_json_driver_scenario_gen.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python2.7
+
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import gen_build_yaml as gen
+import json
+
+def generate_args():
+    all_scenario_set = gen.generate_yaml()
+    all_scenario_set = all_scenario_set['tests']
+    qps_json_driver_scenario_set = \
+        [item for item in all_scenario_set if item['name'] == 'qps_json_driver']
+    qps_json_driver_arg_set = \
+        [item['args'][2] for item in qps_json_driver_scenario_set \
+        if 'args' in item and len(item['args']) > 2]
+    deserialized_scenarios = [json.loads(item)['scenarios'][0] \
+                            for item in qps_json_driver_arg_set]
+    all_scenarios = {scenario['name'].encode('ascii', 'ignore'): \
+                   '\'{\'scenarios\' : [' + json.dumps(scenario) + ']}\'' \
+                   for scenario in deserialized_scenarios}
+
+    serialized_scenarios_str = str(all_scenarios).encode('ascii', 'ignore')
+    with open('qps_json_driver_scenarios.bzl', 'w') as f:
+        f.write('"""Scenarios of qps driver."""\n\n')
+        f.write('QPS_JSON_DRIVER_SCENARIOS = ' + serialized_scenarios_str + '\n')
+
+generate_args()

test/cpp/util/cli_credentials.cc

@@ -28,7 +28,8 @@ DEFINE_bool(use_auth, false,
             "--channel_creds_type=gdc.");
 DEFINE_string(
     access_token, "",
-    "The access token that will be sent to the server to authenticate RPCs.");
+    "The access token that will be sent to the server to authenticate RPCs. "
+    "Deprecated. Use --call_creds=access_token=<token>.");
 DEFINE_string(
     ssl_target, "",
     "If not empty, treat the server host name as this for ssl/tls certificate "
@@ -37,10 +38,34 @@ DEFINE_string(
     channel_creds_type, "",
     "The channel creds type: insecure, ssl, gdc (Google Default Credentials) "
     "or alts.");
+DEFINE_string(
+    call_creds, "",
+    "Call credentials to use: none (default), or access_token=<token>. If "
+    "provided, the call creds are composited on top of channel creds.");
 
 namespace grpc {
 namespace testing {
 
+namespace {
+
+const char ACCESS_TOKEN_PREFIX[] = "access_token=";
+constexpr int ACCESS_TOKEN_PREFIX_LEN =
+    sizeof(ACCESS_TOKEN_PREFIX) / sizeof(*ACCESS_TOKEN_PREFIX) - 1;
+
+bool IsAccessToken(const grpc::string& auth) {
+  return auth.length() > ACCESS_TOKEN_PREFIX_LEN &&
+         auth.compare(0, ACCESS_TOKEN_PREFIX_LEN, ACCESS_TOKEN_PREFIX) == 0;
+}
+
+grpc::string AccessToken(const grpc::string& auth) {
+  if (!IsAccessToken(auth)) {
+    return "";
+  }
+  return grpc::string(auth, ACCESS_TOKEN_PREFIX_LEN);
+}
+
+}  // namespace
+
 grpc::string CliCredentials::GetDefaultChannelCredsType() const {
   // Compatibility logic for --enable_ssl.
   if (FLAGS_enable_ssl) {
@@ -59,6 +84,16 @@ grpc::string CliCredentials::GetDefaultChannelCredsType() const {
   return "insecure";
 }
 
+grpc::string CliCredentials::GetDefaultCallCreds() const {
+  if (!FLAGS_access_token.empty()) {
+    fprintf(stderr,
+            "warning: --access_token is deprecated. Use "
+            "--call_creds=access_token=<token>.\n");
+    return grpc::string("access_token=") + FLAGS_access_token;
+  }
+  return "none";
+}
+
 std::shared_ptr<grpc::ChannelCredentials>
 CliCredentials::GetChannelCredentials() const {
   if (FLAGS_channel_creds_type.compare("insecure") == 0) {
@@ -80,18 +115,30 @@ CliCredentials::GetChannelCredentials() const {
 
 std::shared_ptr<grpc::CallCredentials> CliCredentials::GetCallCredentials()
     const {
-  if (!FLAGS_access_token.empty()) {
-    if (FLAGS_use_auth) {
-      fprintf(stderr,
-              "warning: use_auth is ignored when access_token is provided.");
-    }
-    return grpc::AccessTokenCredentials(FLAGS_access_token);
+  if (IsAccessToken(FLAGS_call_creds)) {
+    return grpc::AccessTokenCredentials(AccessToken(FLAGS_call_creds));
   }
+  if (FLAGS_call_creds.compare("none") != 0) {
+    // Nothing to do; creds, if any, are baked into the channel.
+    return std::shared_ptr<grpc::CallCredentials>();
+  }
+  fprintf(stderr,
+          "--call_creds=%s invalid; must be none "
+          "or access_token=<token>.\n",
+          FLAGS_call_creds.c_str());
   return std::shared_ptr<grpc::CallCredentials>();
 }
 
 std::shared_ptr<grpc::ChannelCredentials> CliCredentials::GetCredentials()
     const {
+  if (FLAGS_call_creds.empty()) {
+    FLAGS_call_creds = GetDefaultCallCreds();
+  } else if (!FLAGS_access_token.empty() && !IsAccessToken(FLAGS_call_creds)) {
+    fprintf(stderr,
+            "warning: ignoring --access_token because --call_creds "
+            "already set to %s.\n",
+            FLAGS_call_creds.c_str());
+  }
   if (FLAGS_channel_creds_type.empty()) {
     FLAGS_channel_creds_type = GetDefaultChannelCredsType();
   } else if (FLAGS_enable_ssl && FLAGS_channel_creds_type.compare("ssl") != 0) {
@@ -106,7 +153,7 @@ std::shared_ptr<grpc::ChannelCredentials> CliCredentials::GetCredentials()
             FLAGS_channel_creds_type.c_str());
   }
   // Legacy transport upgrade logic for insecure requests.
-  if (!FLAGS_access_token.empty() &&
+  if (IsAccessToken(FLAGS_call_creds) &&
       FLAGS_channel_creds_type.compare("insecure") == 0) {
     fprintf(stderr,
             "warning: --channel_creds_type=insecure upgraded to ssl because "
@@ -126,10 +173,14 @@ const grpc::string CliCredentials::GetCredentialUsage() const {
   return "    --enable_ssl             ; Set whether to use ssl (deprecated)\n"
          "    --use_auth               ; Set whether to create default google"
          " credentials\n"
+         "                             ; (deprecated)\n"
          "    --access_token           ; Set the access token in metadata,"
          " overrides --use_auth\n"
+         "                             ; (deprecated)\n"
          "    --ssl_target             ; Set server host for ssl validation\n"
-         "    --channel_creds_type     ; Set to insecure, ssl, gdc, or alts\n";
+         "    --channel_creds_type     ; Set to insecure, ssl, gdc, or alts\n"
+         "    --call_creds             ; Set to none, or"
+         " access_token=<token>\n";
 }
 
 const grpc::string CliCredentials::GetSslTargetNameOverride() const {

test/cpp/util/cli_credentials.h

@@ -36,6 +36,9 @@ class CliCredentials {
   // Returns the appropriate channel_creds_type value for the set of legacy
   // flag arguments.
   virtual grpc::string GetDefaultChannelCredsType() const;
+  // Returns the appropriate call_creds value for the set of legacy flag
+  // arguments.
+  virtual grpc::string GetDefaultCallCreds() const;
   // Returns the base transport channel credentials. Child classes can override
   // to support additional channel_creds_types unknown to this base class.
   virtual std::shared_ptr<grpc::ChannelCredentials> GetChannelCredentials()

tools/dockerfile/interoptest/grpc_interop_dart/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM google/dart:latest
+FROM google/dart:2.0
 
 # Upgrade Dart to version 2.
 RUN apt-get update && apt-get upgrade -y dart