Update C++ compiler to prefix enum and messages defined with no package name to avoid C include collisions.

PiperOrigin-RevId: 489023142

protos_generator/gen_enums.cc

@@ -27,6 +27,7 @@
 
 #include "google/protobuf/descriptor.pb.h"
 #include "google/protobuf/descriptor.h"
+#include "protos_generator/gen_utils.h"
 
 namespace protos_generator {
 
@@ -53,12 +54,22 @@ std::string EnumTypeName(const protobuf::EnumDescriptor* enum_descriptor) {
     // enums types with no package name are prefixed with protos_ to prevent
     // conflicts with generated C headers.
     if (enum_descriptor->file()->package().empty()) {
-      return absl::StrCat("protos_", ToCIdent(enum_descriptor->name()));
+      return absl::StrCat(kNoPackageNamePrefix,
+                          ToCIdent(enum_descriptor->name()));
     }
     return ToCIdent(enum_descriptor->name());
   } else {
-    return ToCIdent(
-        absl::StrCat(containing_type->name(), "_", enum_descriptor->name()));
+    // Since the enum is in global name space (no package), it will have the
+    // same classified name as the C header include, to prevent collision
+    // rename as above.
+    if (containing_type->file()->package().empty()) {
+      return ToCIdent(absl::StrCat(containing_type->name(), "_",
+                                   kNoPackageNamePrefix,
+                                   enum_descriptor->name()));
+    } else {
+      return ToCIdent(
+          absl::StrCat(containing_type->name(), "_", enum_descriptor->name()));
+    }
   }
 }
 
@@ -73,7 +84,7 @@ std::string EnumValueSymbolInNameSpace(
     // protos enum values with no package name are prefixed with protos_ to
     // prevent conflicts with generated C headers.
     if (desc->file()->package().empty()) {
-      return absl::StrCat("protos_", ToCIdent(value->name()));
+      return absl::StrCat(kNoPackageNamePrefix, ToCIdent(value->name()));
     }
     return ToCIdent(value->name());
   }

protos_generator/gen_utils.cc

@@ -73,6 +73,13 @@ std::string QualifiedFileLevelSymbol(const protobuf::FileDescriptor* file,
 std::string ClassName(const protobuf::Descriptor* descriptor) {
   const protobuf::Descriptor* parent = descriptor->containing_type();
   std::string res;
+  // Classes in global namespace without package names are prefixed
+  // by protos_ to avoid collision with C compiler structs defined in
+  // proto.upb.h.
+  if ((parent && parent->file()->package().empty()) ||
+      descriptor->file()->package().empty()) {
+    res = std::string(kNoPackageNamePrefix);
+  }
   if (parent) res += ClassName(parent) + "_";
   absl::StrAppend(&res, descriptor->name());
   return ::upbc::ResolveKeywordConflict(res);

protos_generator/gen_utils.h

@@ -30,6 +30,7 @@
 
 #include "google/protobuf/descriptor.pb.h"
 #include "absl/container/flat_hash_map.h"
+#include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/code_generator.h"
 #include "google/protobuf/compiler/plugin.h"
 #include "google/protobuf/descriptor.h"
@@ -76,6 +77,8 @@ std::string MessageCProxyType(const protobuf::FieldDescriptor* field,
 std::string MessageProxyType(const protobuf::FieldDescriptor* field,
                              bool is_const);
 
+inline constexpr absl::string_view kNoPackageNamePrefix = "protos_";
+
 }  // namespace protos_generator
 
 #endif  // UPB_PROTOS_GENERATOR_GEN_UTILS_H_

protos_generator/tests/BUILD

@@ -59,6 +59,14 @@ proto_library(
     ],
 )
 
+proto_library(
+    name = "no_package_enum_user_proto",
+    srcs = [
+        "no_package_enum_user.proto",
+    ],
+    deps = [":no_package_proto"],
+)
+
 upb_proto_library(
     name = "test_model_upb_proto",
     visibility = [
@@ -78,7 +86,16 @@ upb_cc_proto_library(
 
 upb_cc_proto_library(
     name = "no_package_upb_cc_proto",
-    deps = [":no_package_proto"],
+    deps = [
+        ":no_package_proto",
+    ],
+)
+
+upb_cc_proto_library(
+    name = "no_package_enum_user_upb_cc_proto",
+    deps = [
+        ":no_package_enum_user_proto",
+    ],
 )
 
 cc_proto_library(

protos_generator/tests/no_package.proto

@@ -6,3 +6,13 @@ enum EnumWithNoPackage {
   CELSIUS = 1;
   FAHRENHEIT = 2;
 }
+
+message MessageWithEnumUpbTest {
+  enum EnumWithNoPackageInMessage {
+    UNKNOWN = 0;
+    AB_1 = 1;
+    CD_2 = 2;
+    EF_3 = 3;
+    GH_4 = 4;
+  }
+}

protos_generator/tests/no_package_enum_user.proto

@@ -0,0 +1,11 @@
+syntax = "proto2";
+
+package protos_generator.tests;
+
+import "protos_generator/tests/no_package.proto";
+
+// option java_multiple_files = true;
+
+message MyMessage {
+  optional MessageWithEnumUpbTest my_type = 1;
+}