Change DynamicCastMessage to throw a `std::bad_cast` exception when exceptions

are enabled.
This makes the function a drop-in replacement for `dynamic_cast` when the user
is expecting exceptions to be thrown.

PiperOrigin-RevId: 689419852

src/google/protobuf/BUILD.bazel

@@ -1268,6 +1268,7 @@ cc_library(
         ":protobuf",
         "//src/google/protobuf/testing",
         "//src/google/protobuf/testing:file",
+        "@com_google_absl//absl/base:config",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/strings",
@@ -1735,6 +1736,7 @@ cc_test(
         "//src/google/protobuf/testing",
         "//src/google/protobuf/testing:file",
         "//src/google/protobuf/util:differencer",
+        "@com_google_absl//absl/base:config",
         "@com_google_absl//absl/hash:hash_testing",
         "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/log:scoped_mock_log",
@@ -1766,6 +1768,7 @@ cc_test(
         "//src/google/protobuf/testing",
         "//src/google/protobuf/testing:file",
         "//src/google/protobuf/util:differencer",
+        "@com_google_absl//absl/base:config",
         "@com_google_absl//absl/log:absl_check",
         "@com_google_absl//absl/log:scoped_mock_log",
         "@com_google_absl//absl/strings",

src/google/protobuf/lite_unittest.cc

@@ -1395,16 +1395,23 @@ TEST(LiteTest, DynamicCastMessage) {
   EXPECT_EQ(shared_2, nullptr);
 }
 
-#if GTEST_HAS_DEATH_TEST
 TEST(LiteTest, DynamicCastMessageInvalidReferenceType) {
   CastType1 test_type_1;
   const MessageLite& test_type_1_pointer_const_ref = test_type_1;
+#if defined(ABSL_HAVE_EXCEPTIONS)
+  EXPECT_THROW(DynamicCastMessage<CastType2>(test_type_1_pointer_const_ref),
+               std::bad_cast);
+#elif defined(GTEST_HAS_DEATH_TEST)
   ASSERT_DEATH(
       DynamicCastMessage<CastType2>(test_type_1_pointer_const_ref),
       absl::StrCat("Cannot downcast ", test_type_1.GetTypeName(), " to ",
                    CastType2::default_instance().GetTypeName()));
+#else
+  (void)test_type_1;
+  (void)test_type_1_pointer_const_ref;
+  GTEST_SKIP() << "Can't test the failure.";
+#endif
 }
-#endif  // GTEST_HAS_DEATH_TEST
 
 TEST(LiteTest, DownCastMessageValidType) {
   CastType1 test_type_1;

src/google/protobuf/message_lite.cc

@@ -19,8 +19,10 @@
 #include <istream>
 #include <ostream>
 #include <string>
+#include <typeinfo>
 #include <utility>
 
+#include "absl/base/config.h"
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
 #include "absl/strings/cord.h"
@@ -198,6 +200,9 @@ void MessageLite::LogInitializationErrorMessage() const {
 namespace internal {
 
 void FailDynamicCast(const MessageLite& from, const MessageLite& to) {
+#if defined(ABSL_HAVE_EXCEPTIONS)
+  throw std::bad_cast();
+#endif
   const auto to_name = to.GetTypeName();
   if (internal::GetClassData(from)->is_dynamic) {
     ABSL_LOG(FATAL)

src/google/protobuf/message_unittest.inc

@@ -35,6 +35,7 @@
 #include <gmock/gmock.h>
 #include "google/protobuf/testing/googletest.h"
 #include <gtest/gtest.h>
+#include "absl/base/config.h"
 #include "absl/log/absl_check.h"
 #include "absl/log/scoped_mock_log.h"
 #include "absl/strings/cord.h"
@@ -816,11 +817,17 @@ TEST(MESSAGE_TEST_NAME, DynamicCastMessage) {
 TEST(MESSAGE_TEST_NAME, DynamicCastMessageInvalidReferenceType) {
   UNITTEST::TestAllTypes test_all_types;
   const MessageLite& test_all_types_pointer_const_ref = test_all_types;
+#if defined(ABSL_HAVE_EXCEPTIONS)
+  EXPECT_THROW(DynamicCastMessage<UNITTEST::TestRequired>(
+                   test_all_types_pointer_const_ref),
+               std::bad_cast);
+#else
   ASSERT_DEATH(
       DynamicCastMessage<UNITTEST::TestRequired>(
           test_all_types_pointer_const_ref),
       absl::StrCat("Cannot downcast ", test_all_types.GetTypeName(), " to ",
                    UNITTEST::TestRequired::default_instance().GetTypeName()));
+#endif
 }
 
 TEST(MESSAGE_TEST_NAME, DownCastMessageValidType) {