Verify more than one message set entities.

PiperOrigin-RevId: 607427370

src/google/protobuf/extension_set_heavy.cc

@@ -16,6 +16,7 @@
 #include <cstdint>
 #include <vector>
 
+#include "absl/base/attributes.h"
 #include "absl/log/absl_check.h"
 #include "google/protobuf/arena.h"
 #include "google/protobuf/descriptor.h"

src/google/protobuf/extension_set_unittest.cc

@@ -44,6 +44,9 @@ namespace protobuf {
 
 
 namespace internal {
+
+extern bool fully_verify_message_sets_opt_out;
+
 namespace {
 
 using ::google::protobuf::internal::DownCast;

src/google/protobuf/fully_verify_message_sets_opt_out.cc

@@ -0,0 +1,9 @@
+namespace google {
+namespace protobuf {
+namespace internal {
+
+bool fully_verify_message_sets_opt_out = true;
+
+}  // namespace internal
+}  // namespace protobuf
+}  // namespace google