# --- T2-COPYRIGHT-BEGIN ---
# t2/package/*/protobuf-c/hotfix.patch
# Copyright (C) 2026 The T2 SDE Project
# SPDX-License-Identifier: GPL-2.0 or patched project license
# --- T2-COPYRIGHT-END ---

See gh #795 https://github.com/protobuf-c/protobuf-c/issues/795#issuecomment-3976758749.

diff --git a/protoc-gen-c/c_bytes_field.cc b/protoc-gen-c/c_bytes_field.cc
index c8ac772..ab10117 100644
--- a/protoc-gen-c/c_bytes_field.cc
+++ b/protoc-gen-c/c_bytes_field.cc
@@ -94,7 +94,7 @@ BytesFieldGenerator::~BytesFieldGenerator() {}
 
 void BytesFieldGenerator::GenerateStructMembers(google::protobuf::io::Printer* printer) const
 {
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(variables_, "ProtobufCBinaryData $name$$deprecated$;\n");
       break;
@@ -135,7 +135,7 @@ std::string BytesFieldGenerator::GetDefaultValue(void) const
 }
 void BytesFieldGenerator::GenerateStaticInit(google::protobuf::io::Printer* printer) const
 {
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(variables_, "$default_value$");
       break;
diff --git a/protoc-gen-c/c_enum_field.cc b/protoc-gen-c/c_enum_field.cc
index c3111f5..78ffb1c 100644
--- a/protoc-gen-c/c_enum_field.cc
+++ b/protoc-gen-c/c_enum_field.cc
@@ -95,7 +95,7 @@ EnumFieldGenerator::~EnumFieldGenerator() {}
 
 void EnumFieldGenerator::GenerateStructMembers(google::protobuf::io::Printer* printer) const
 {
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(variables_, "$type$ $name$$deprecated$;\n");
       break;
@@ -117,7 +117,7 @@ std::string EnumFieldGenerator::GetDefaultValue(void) const
 }
 void EnumFieldGenerator::GenerateStaticInit(google::protobuf::io::Printer* printer) const
 {
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(variables_, "$default$");
       break;
diff --git a/protoc-gen-c/c_field.cc b/protoc-gen-c/c_field.cc
index 8d22343..8f83e1b 100644
--- a/protoc-gen-c/c_field.cc
+++ b/protoc-gen-c/c_field.cc
@@ -125,11 +125,11 @@ void FieldGenerator::GenerateDescriptorInitializerGeneric(google::protobuf::io::
     variables["oneofname"] = CamelToLower(oneof->name());
 
   if (FieldSyntax(descriptor_) == 3 &&
-    descriptor_->label() == google::protobuf::FieldDescriptor::LABEL_OPTIONAL) {
+    FieldLabel(descriptor_) == google::protobuf::FieldDescriptor::LABEL_OPTIONAL) {
     variables["LABEL"] = "NONE";
     optional_uses_has = false;
   } else {
-    variables["LABEL"] = CamelToUpper(GetLabelName(descriptor_->label()));
+    variables["LABEL"] = CamelToUpper(GetLabelName(FieldLabel(descriptor_)));
   }
 
   if (descriptor_->has_default_value()) {
@@ -145,11 +145,11 @@ void FieldGenerator::GenerateDescriptorInitializerGeneric(google::protobuf::io::
 
   variables["flags"] = "0";
 
-  if (descriptor_->label() == google::protobuf::FieldDescriptor::LABEL_REPEATED
+  if (FieldLabel(descriptor_) == google::protobuf::FieldDescriptor::LABEL_REPEATED
    && is_packable_type (descriptor_->type())
    && descriptor_->options().packed()) {
     variables["flags"] += " | PROTOBUF_C_FIELD_FLAG_PACKED";
-  } else if (descriptor_->label() == google::protobuf::FieldDescriptor::LABEL_REPEATED
+  } else if (FieldLabel(descriptor_) == google::protobuf::FieldDescriptor::LABEL_REPEATED
    && is_packable_type (descriptor_->type())
    && FieldSyntax(descriptor_) == 3
    && !descriptor_->options().has_packed()) {
@@ -179,7 +179,7 @@ void FieldGenerator::GenerateDescriptorInitializerGeneric(google::protobuf::io::
     "  $value$,\n"
     "  PROTOBUF_C_LABEL_$LABEL$,\n"
     "  PROTOBUF_C_TYPE_$TYPE$,\n");
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(variables, "  0,   /* quantifier_offset */\n");
       break;
diff --git a/protoc-gen-c/c_helpers.cc b/protoc-gen-c/c_helpers.cc
index e5c177c..fcfc258 100644
--- a/protoc-gen-c/c_helpers.cc
+++ b/protoc-gen-c/c_helpers.cc
@@ -338,6 +338,17 @@ std::string GetLabelName(google::protobuf::FieldDescriptor::Label label) {
   return "bad-label";
 }
 
+google::protobuf::FieldDescriptor::Label FieldLabel(
+    const google::protobuf::FieldDescriptor* field) {
+  if (field->is_repeated()) {
+    return google::protobuf::FieldDescriptor::LABEL_REPEATED;
+  }
+  if (field->is_required()) {
+    return google::protobuf::FieldDescriptor::LABEL_REQUIRED;
+  }
+  return google::protobuf::FieldDescriptor::LABEL_OPTIONAL;
+}
+
 unsigned
 WriteIntRanges(google::protobuf::io::Printer* printer, int n_values, const int *values, compat::StringView name)
 {
diff --git a/protoc-gen-c/c_helpers.h b/protoc-gen-c/c_helpers.h
index 6936999..210f17a 100644
--- a/protoc-gen-c/c_helpers.h
+++ b/protoc-gen-c/c_helpers.h
@@ -153,6 +153,11 @@ std::string FilenameIdentifier(compat::StringView filename);
 // return 'required', 'optional', or 'repeated'
 std::string GetLabelName(google::protobuf::FieldDescriptor::Label label);
 
+// Returns the field label in a way that is compatible with protobuf versions
+// where FieldDescriptor::label() is unavailable.
+google::protobuf::FieldDescriptor::Label FieldLabel(
+  const google::protobuf::FieldDescriptor* field);
+
 // write IntRanges entries for a bunch of sorted values.
 // returns the number of ranges there are to bsearch.
 unsigned WriteIntRanges(google::protobuf::io::Printer* printer, int n_values, const int *values, compat::StringView name);
diff --git a/protoc-gen-c/c_message_field.cc b/protoc-gen-c/c_message_field.cc
index 9fca920..4366135 100644
--- a/protoc-gen-c/c_message_field.cc
+++ b/protoc-gen-c/c_message_field.cc
@@ -83,7 +83,7 @@ void MessageFieldGenerator::GenerateStructMembers(google::protobuf::io::Printer*
   vars["name"] = FieldName(descriptor_);
   vars["type"] = FullNameToC(descriptor_->message_type()->full_name(), descriptor_->message_type()->file());
   vars["deprecated"] = FieldDeprecated(descriptor_);
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
     case google::protobuf::FieldDescriptor::LABEL_OPTIONAL:
       printer->Print(vars, "$type$ *$name$$deprecated$;\n");
@@ -103,7 +103,7 @@ std::string MessageFieldGenerator::GetDefaultValue(void) const
 }
 void MessageFieldGenerator::GenerateStaticInit(google::protobuf::io::Printer* printer) const
 {
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
     case google::protobuf::FieldDescriptor::LABEL_OPTIONAL:
       printer->Print("NULL");
diff --git a/protoc-gen-c/c_primitive_field.cc b/protoc-gen-c/c_primitive_field.cc
index 588f60e..b3a4a46 100644
--- a/protoc-gen-c/c_primitive_field.cc
+++ b/protoc-gen-c/c_primitive_field.cc
@@ -109,7 +109,7 @@ void PrimitiveFieldGenerator::GenerateStructMembers(google::protobuf::io::Printe
   vars["name"] = FieldName(descriptor_);
   vars["deprecated"] = FieldDeprecated(descriptor_);
 
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(vars, "$c_type$ $name$$deprecated$;\n");
       break;
@@ -156,7 +156,7 @@ void PrimitiveFieldGenerator::GenerateStaticInit(google::protobuf::io::Printer*
   } else {
     vars["default_value"] = "0";
   }
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
       printer->Print(vars, "$default_value$");
       break;
diff --git a/protoc-gen-c/c_string_field.cc b/protoc-gen-c/c_string_field.cc
index 163f424..6aea8dd 100644
--- a/protoc-gen-c/c_string_field.cc
+++ b/protoc-gen-c/c_string_field.cc
@@ -94,7 +94,7 @@ void StringFieldGenerator::GenerateStructMembers(google::protobuf::io::Printer*
 {
   const ProtobufCFileOptions opt = descriptor_->file()->options().GetExtension(pb_c_file);
 
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
     case google::protobuf::FieldDescriptor::LABEL_OPTIONAL:
       if (opt.const_strings())
@@ -138,7 +138,7 @@ void StringFieldGenerator::GenerateStaticInit(google::protobuf::io::Printer* pri
   } else {
     vars["default"] = "(char *)protobuf_c_empty_string";
   }
-  switch (descriptor_->label()) {
+  switch (FieldLabel(descriptor_)) {
     case google::protobuf::FieldDescriptor::LABEL_REQUIRED:
     case google::protobuf::FieldDescriptor::LABEL_OPTIONAL:
       printer->Print(vars, "$default$");