Add more info to metadata limit exceeded error (#31756)

* Add more info to error

* Fix tests

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

@@ -26,6 +26,7 @@
 #include <stdlib.h>
 
 #include <algorithm>
+#include <cinttypes>
 #include <string>
 #include <utility>
 
@@ -1190,16 +1191,15 @@ class HPackParser::Parser {
 
   GPR_ATTRIBUTE_NOINLINE
   bool HandleMetadataSizeLimitExceeded(const HPackTable::Memento&) {
-    gpr_log(GPR_DEBUG,
-            "received initial metadata size exceeds limit (%" PRIu32
-            " vs. %" PRIu32
-            "). GRPC_ARG_MAX_METADATA_SIZE can be set to increase this limit.",
-            *frame_length_, metadata_size_limit_);
     if (metadata_buffer_ != nullptr) metadata_buffer_->Clear();
+    // TODO(alishananda): add debug log with metadata details
     return input_->MaybeSetErrorAndReturn(
-        [] {
+        [this] {
           return grpc_error_set_int(
-              GRPC_ERROR_CREATE("received initial metadata size exceeds limit"),
+              GRPC_ERROR_CREATE(absl::StrFormat(
+                  "received initial metadata size exceeds limit (%" PRIu32
+                  " vs. %" PRIu32 ")",
+                  *frame_length_, metadata_size_limit_)),
               StatusIntProperty::kRpcStatus, GRPC_STATUS_RESOURCE_EXHAUSTED);
         },
         false);

test/core/end2end/tests/large_metadata.cc

@@ -353,10 +353,13 @@ static void test_request_with_bad_large_metadata_response(
   cqv.Verify();
 
   GPR_ASSERT(status == GRPC_STATUS_RESOURCE_EXHAUSTED);
-  GPR_ASSERT(0 == grpc_slice_str_cmp(
-                      details, "received initial metadata size exceeds limit"));
+  const char* expected_error = "received initial metadata size exceeds limit";
+  grpc_slice actual_error =
+      grpc_slice_split_head(&details, strlen(expected_error));
+  GPR_ASSERT(0 == grpc_slice_str_cmp(actual_error, expected_error));
   GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
 
+  grpc_slice_unref(actual_error);
   grpc_slice_unref(details);
   grpc_metadata_array_destroy(&initial_metadata_recv);
   grpc_metadata_array_destroy(&trailing_metadata_recv);