protocolbuffers · copybara-service · Feb 9, 2026
diff --git a/conformance/binary_json_conformance_suite.cc b/conformance/binary_json_conformance_suite.cc
@@ -324,6 +324,7 @@ void BinaryAndJsonConformanceSuite::RunSuiteImpl() {
       RunUtf8ValidationTests();
     }
   }
+  RunRecursionLimitTests();
 }
 
 void BinaryAndJsonConformanceSuite::RunDelimitedFieldTests() {
@@ -490,6 +491,36 @@ void BinaryAndJsonConformanceSuite::RunMessageSetTests() {
   );
 }
 
+void BinaryAndJsonConformanceSuite::RunRecursionLimitTests() {
+  {
+    TestAllTypesEdition2023 message;
+    TestAllTypesEdition2023* sub = &message;
+    for (int i = 0; i < 101; i++) {
+      sub = &(*sub->mutable_map_recursive())[0];
+      sub->set_optional_int32(123);
+    }
+    ExpectParseFailureForProto<TestAllTypesEdition2023>(
+        message.SerializeAsString(), "EnforceDepthLimit.Map", REQUIRED);
+  }
+
+  {
+    TestAllTypesProto2 proto2_msg;
+    auto sub = proto2_msg.mutable_message_set_correct();
+    for (int i = 0; i < 50; i++) {
+      sub = sub->MutableExtension(
+                   TestAllTypesProto2::MessageSetCorrectExtension2::
+                       message_set_extension)
+                ->mutable_sub_msg();
+    }
+    sub->MutableExtension(TestAllTypesProto2::MessageSetCorrectExtension2::
+                              message_set_extension)
+        ->set_i(123);
+    ExpectParseFailureForProto<TestAllTypesProto2>(
+        proto2_msg.SerializeAsString(), "EnforceDepthLimit.MessageSetExtension",
+        REQUIRED);
+  }
+}
+
 template <typename MessageType>
 void BinaryAndJsonConformanceSuite::ExpectParseFailureForProto(
     const std::string& proto, const std::string& test_name,

diff --git a/conformance/binary_json_conformance_suite.h b/conformance/binary_json_conformance_suite.h
@@ -68,6 +68,8 @@ class BinaryAndJsonConformanceSuite : public ConformanceTestSuite {
 
   void RunMessageSetTests();
 
+  void RunRecursionLimitTests();
+
   template <typename MessageType>
   friend class BinaryAndJsonConformanceSuiteImpl;
 

diff --git a/conformance/failure_list_csharp.txt b/conformance/failure_list_csharp.txt
@@ -41,3 +41,4 @@ Required.*.ProtobufInput.BadTag_FieldNumberTooHigh
 Required.*.ProtobufInput.BadTag_FieldNumberSlightlyTooHigh                                                         # Should have failed to parse, but didn't.
 Required.*.ProtobufInput.BadTag_OverlongVarint                                                                     # Should have failed to parse, but didn't.
 Required.*.JsonInput.AnyEmpty.*
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension                                                # Should have failed to parse, but didn't.
diff --git a/conformance/failure_list_java.txt b/conformance/failure_list_java.txt
@@ -53,3 +53,4 @@ Required.*.ProtobufInput.BadTag_OverlongVarint
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Oneof                                                    # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Repeated                                                 # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Singular                                                 # Should have failed to parse, but didn't.
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension                                                # Should have failed to parse, but didn't.
diff --git a/conformance/failure_list_jruby.txt b/conformance/failure_list_jruby.txt
@@ -147,6 +147,7 @@ Required.Proto3.ProtobufInput.UnknownOrdering.ProtobufOutput
 Required.*.ProtobufInput.BadTag_FieldNumberTooHigh                                                                 # Should have failed to parse, but didn't.
 Required.*.ProtobufInput.BadTag_FieldNumberSlightlyTooHigh                                                         # Should have failed to parse, but didn't.
 Required.*.ProtobufInput.BadTag_OverlongVarint                                                                     # Should have failed to parse, but didn't.
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension                                                # Should have failed to parse, but didn't.
 # TODO: Uncomment once conformance tests can express failures that are not expected to be fixed.
 # Recommended.Editions_Proto2.ProtobufInput.RejectInvalidUtf8.String.Oneof                                           # Should have failed to parse, but didn't.
 # Recommended.Editions_Proto2.ProtobufInput.RejectInvalidUtf8.String.Repeated                                        # Should have failed to parse, but didn't.

diff --git a/conformance/failure_list_objc.txt b/conformance/failure_list_objc.txt
@@ -1,2 +1,3 @@
 # JSON input or output tests are skipped (in conformance_objc.m) as mobile
 # platforms don't support JSON wire format to avoid code bloat.
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension                                                # Should have failed to parse, but didn't.
diff --git a/conformance/failure_list_rust_upb.txt b/conformance/failure_list_rust_upb.txt
@@ -10,3 +10,4 @@ Recommended.Editions.ProtobufInput.RejectInvalidUtf8.String.Extension         #
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Oneof               # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Repeated            # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Singular            # Should have failed to parse, but didn't.
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension             # Should have failed to parse, but didn't.
diff --git a/conformance/test_protos/test_messages_edition2023.proto b/conformance/test_protos/test_messages_edition2023.proto
@@ -191,6 +191,9 @@ message TestAllTypesEdition2023 {
   }
   GroupLikeType groupliketype = 201;
   GroupLikeType delimited_field = 202;
+
+  // recursive
+  map<int32, TestAllTypesEdition2023> map_recursive = 301;
 }
 
 message ForeignMessageEdition2023 {

diff --git a/editions/golden/edition2023_transform/test_messages_proto2.proto b/editions/golden/edition2023_transform/test_messages_proto2.proto
@@ -342,6 +342,7 @@ message TestAllTypesProto2 {
     }
 
     int32 i = 9;
+    MessageSetCorrect sub_msg = 10;
   }
 
   message ExtensionWithOneof {

diff --git a/editions/golden/edition2024_transform/test_messages_proto2.proto b/editions/golden/edition2024_transform/test_messages_proto2.proto
@@ -355,6 +355,7 @@ message TestAllTypesProto2 {
     }
 
     int32 i = 9;
+    MessageSetCorrect sub_msg = 10;
   }
 
   message ExtensionWithOneof {

diff --git a/editions/golden/test_messages_proto2_editions.proto b/editions/golden/test_messages_proto2_editions.proto
@@ -342,6 +342,7 @@ message TestAllTypesProto2 {
     }
 
     int32 i = 9;
+    MessageSetCorrect sub_msg = 10;
   }
 
   message ExtensionWithOneof {

diff --git a/src/google/protobuf/test_messages_proto2.proto b/src/google/protobuf/test_messages_proto2.proto
@@ -242,6 +242,7 @@ message TestAllTypesProto2 {
       optional MessageSetCorrectExtension2 message_set_extension = 4135312;
     }
     optional int32 i = 9;
+    optional MessageSetCorrect sub_msg = 10;
   }
 
   message ExtensionWithOneof {

diff --git a/upb/conformance/conformance_upb_failures.txt b/upb/conformance/conformance_upb_failures.txt
@@ -14,3 +14,4 @@ Required.*.JsonInput.AnyWithNoType.*                                        # Fa
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Oneof             # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Repeated          # Should have failed to parse, but didn't.
 # Recommended.Proto2.ProtobufInput.RejectInvalidUtf8.String.Singular          # Should have failed to parse, but didn't.
+Required.Proto2.ProtobufInput.EnforceDepthLimit.MessageSetExtension          # Should have failed to parse, but didn't.
-Original file line number
+Diff line change
@@ Expand Up / @@ -342,6 +342,7 @@ message TestAllTypesProto2 { @@
         }
         int32 i = 9;
+        MessageSetCorrect sub_msg = 10;
       }
       message ExtensionWithOneof {
@@ Expand Down @@