Fix C# parsing of delimited fields.

Instead of using the message's corresponding field to denote the end of the stream, just abort it on *any* end group tag.  If this is an invalid tag, the caller will handle the failure.

PiperOrigin-RevId: 622859234

conformance/failure_list_csharp.txt

@@ -33,8 +33,3 @@ Recommended.Editions_Proto3.ValueRejectInfNumberValue.JsonOutput
 Recommended.Editions_Proto3.ValueRejectNanNumberValue.JsonOutput
 Required.Editions_Proto2.ProtobufInput.UnknownOrdering.ProtobufOutput
 Required.Editions_Proto3.ProtobufInput.UnknownOrdering.ProtobufOutput
-
-# TODO C# doesn't handle delimited parsing well.
-Required.Editions.ProtobufInput.ValidDelimitedExtension.NotGroupLike.ProtobufOutput
-Required.Editions.ProtobufInput.ValidDelimitedField.NotGroupLike.JsonOutput
-Required.Editions.ProtobufInput.ValidDelimitedField.NotGroupLike.ProtobufOutput

src/google/protobuf/compiler/csharp/csharp_helpers.cc

@@ -192,44 +192,6 @@ std::string GetEnumValueName(absl::string_view enum_name,
   return result;
 }
 
-uint GetGroupEndTag(const Descriptor* descriptor) {
-  const Descriptor* containing_type = descriptor->containing_type();
-  if (containing_type != nullptr) {
-    const FieldDescriptor* field;
-    for (int i = 0; i < containing_type->field_count(); i++) {
-      field = containing_type->field(i);
-      if (field->type() == FieldDescriptor::Type::TYPE_GROUP &&
-          field->message_type() == descriptor) {
-        return internal::WireFormatLite::MakeTag(
-            field->number(), internal::WireFormatLite::WIRETYPE_END_GROUP);
-      }
-    }
-    for (int i = 0; i < containing_type->extension_count(); i++) {
-      field = containing_type->extension(i);
-      if (field->type() == FieldDescriptor::Type::TYPE_GROUP &&
-          field->message_type() == descriptor) {
-        return internal::WireFormatLite::MakeTag(
-            field->number(), internal::WireFormatLite::WIRETYPE_END_GROUP);
-      }
-    }
-  } else {
-    const FileDescriptor* containing_file = descriptor->file();
-    if (containing_file != nullptr) {
-      const FieldDescriptor* field;
-      for (int i = 0; i < containing_file->extension_count(); i++) {
-        field = containing_file->extension(i);
-        if (field->type() == FieldDescriptor::Type::TYPE_GROUP &&
-            field->message_type() == descriptor) {
-          return internal::WireFormatLite::MakeTag(
-              field->number(), internal::WireFormatLite::WIRETYPE_END_GROUP);
-        }
-      }
-    }
-  }
-
-  return 0;
-}
-
 std::string GetFullExtensionName(const FieldDescriptor* descriptor) {
   if (descriptor->extension_scope()) {
     return absl::StrCat(GetClassName(descriptor->extension_scope()),

src/google/protobuf/compiler/csharp/csharp_helpers.h

@@ -85,9 +85,6 @@ inline bool IsMapEntryMessage(const Descriptor* descriptor) {
   return descriptor->options().map_entry();
 }
 
-// Checks if this descriptor is for a group and gets its end tag or 0 if it's not a group
-uint GetGroupEndTag(const Descriptor* descriptor);
-
 // Determines whether we're generating code for the proto representation of
 // descriptors etc, for use in the runtime. This is the only type which is
 // allowed to use proto2 syntax, and it generates internal classes.

src/google/protobuf/compiler/csharp/csharp_message.cc

@@ -43,7 +43,6 @@ MessageGenerator::MessageGenerator(const Descriptor* descriptor,
     : SourceGeneratorBase(options),
       descriptor_(descriptor),
       has_bit_field_count_(0),
-      end_tag_(GetGroupEndTag(descriptor)),
       has_extension_ranges_(descriptor->extension_range_count() > 0) {
   // fields by number
   for (int i = 0; i < descriptor_->field_count(); i++) {
@@ -668,18 +667,17 @@ void MessageGenerator::GenerateMainParseLoop(io::Printer* printer,
   absl::flat_hash_map<absl::string_view, std::string> vars;
   vars["maybe_ref_input"] = use_parse_context ? "ref input" : "input";
 
-  printer->Print(
-      "uint tag;\n"
-      "while ((tag = input.ReadTag()) != 0) {\n"
-      "  switch(tag) {\n");
+  printer->Emit(R"csharp(
+    uint tag;
+    while ((tag = input.ReadTag()) != 0) {
+    if ((tag & 7) == 4) {
+      // Abort on any end group tag.
+      return;
+    }
+    switch(tag) {
+  )csharp");
   printer->Indent();
   printer->Indent();
-  if (end_tag_ != 0) {
-    printer->Print(
-        "case $end_tag$:\n"
-        "  return;\n",
-        "end_tag", absl::StrCat(end_tag_));
-  }
   if (has_extension_ranges_) {
     printer->Print(vars,
                    "default:\n"

src/google/protobuf/compiler/csharp/csharp_message.h

@@ -39,7 +39,6 @@ class MessageGenerator : public SourceGeneratorBase {
   const Descriptor* descriptor_;
   std::vector<const FieldDescriptor*> fields_by_number_;
   int has_bit_field_count_;
-  uint end_tag_;
   bool has_extension_ranges_;
 
   void GenerateMessageSerializationMethods(io::Printer* printer);