upb: remove the default arg from upb_Message_GetMessage()

PiperOrigin-RevId: 603225526

upb/message/accessors.h

diff --git a/upb/message/accessors.h b/upb/message/accessors.h
index cab7323..64f770b 100644
--- a/upb/message/accessors.h
+++ b/upb/message/accessors.h
@@ -329,16 +329,15 @@
 }
 
 UPB_API_INLINE const upb_Message* upb_Message_GetMessage(
-    const upb_Message* msg, const upb_MiniTableField* field,
-    upb_Message* default_val) {
+    const upb_Message* msg, const upb_MiniTableField* field) {
   upb_TaggedMessagePtr tagged =
-      upb_Message_GetTaggedMessagePtr(msg, field, default_val);
+      upb_Message_GetTaggedMessagePtr(msg, field, NULL);
   return upb_TaggedMessagePtr_GetNonEmptyMessage(tagged);
 }
 
 UPB_API_INLINE upb_Message* upb_Message_GetMutableMessage(
     upb_Message* msg, const upb_MiniTableField* field) {
-  return (upb_Message*)upb_Message_GetMessage(msg, field, NULL);
+  return (upb_Message*)upb_Message_GetMessage(msg, field);
 }
 
 // For internal use only; users cannot set tagged messages because only the

upb/message/accessors_test.cc

diff --git a/upb/message/accessors_test.cc b/upb/message/accessors_test.cc
index 59a5e51..5b0dd36 100644
--- a/upb/message/accessors_test.cc
+++ b/upb/message/accessors_test.cc
@@ -289,7 +289,7 @@
       find_proto2_field(kFieldOptionalNestedMessage);
 
   const upb_Message* test_message =
-      upb_Message_GetMessage(UPB_UPCAST(msg), optional_message_field, nullptr);
+      upb_Message_GetMessage(UPB_UPCAST(msg), optional_message_field);
   EXPECT_EQ(nullptr, test_message);
 
   EXPECT_EQ(false,
@@ -307,7 +307,7 @@
 
   // Read back using mini table API.
   const upb_Message* sub_message =
-      upb_Message_GetMessage(UPB_UPCAST(msg), optional_message_field, nullptr);
+      upb_Message_GetMessage(UPB_UPCAST(msg), optional_message_field);
   EXPECT_EQ(true, sub_message != nullptr);
 
   const upb_MiniTableField* nested_message_a_field =

upb/message/copy_test.cc

diff --git a/upb/message/copy_test.cc b/upb/message/copy_test.cc
index 0ec87e4..8434258 100644
--- a/upb/message/copy_test.cc
+++ b/upb/message/copy_test.cc
@@ -127,8 +127,7 @@
   protobuf_test_messages_proto2_TestAllTypesProto2_NestedMessage*
       cloned_nested =
           (protobuf_test_messages_proto2_TestAllTypesProto2_NestedMessage*)
-              upb_Message_GetMessage(UPB_UPCAST(clone), nested_message_field,
-                                     nullptr);
+              upb_Message_GetMessage(UPB_UPCAST(clone), nested_message_field);
   EXPECT_EQ(protobuf_test_messages_proto2_TestAllTypesProto2_NestedMessage_a(
                 cloned_nested),
             kTestNestedInt32);

upb/message/promote.c

diff --git a/upb/message/promote.c b/upb/message/promote.c
index 3c07491..51412e1 100644
--- a/upb/message/promote.c
+++ b/upb/message/promote.c
@@ -243,7 +243,7 @@
   bool is_oneof = upb_MiniTableField_IsInOneof(field);
   if (!is_oneof || UPB_PRIVATE(_upb_Message_GetOneofCase)(msg, field) ==
                        upb_MiniTableField_Number(field)) {
-    UPB_ASSERT(upb_Message_GetMessage(msg, field, NULL) == NULL);
+    UPB_ASSERT(upb_Message_GetMessage(msg, field) == NULL);
   }
   upb_UnknownToMessageRet ret;
   ret.status = kUpb_UnknownToMessage_Ok;

upb/message/promote_test.cc

diff --git a/upb/message/promote_test.cc b/upb/message/promote_test.cc
index 1dc8932..19ca17d 100644
--- a/upb/message/promote_test.cc
+++ b/upb/message/promote_test.cc
@@ -390,8 +390,7 @@
                                  arena.ptr(), (upb_Message**)&promoted);
   EXPECT_EQ(promote_result, kUpb_DecodeStatus_Ok);
   EXPECT_NE(nullptr, promoted);
-  EXPECT_EQ(UPB_UPCAST(promoted),
-            upb_Message_GetMessage(msg, submsg_field, nullptr));
+  EXPECT_EQ(UPB_UPCAST(promoted), upb_Message_GetMessage(msg, submsg_field));
   EXPECT_EQ(upb_test_ModelWithExtensions_random_int32(promoted), 12);
 }
 
@@ -439,8 +438,7 @@
                                  arena.ptr(), (upb_Message**)&promoted);
   EXPECT_EQ(promote_result, kUpb_DecodeStatus_Ok);
   EXPECT_NE(nullptr, promoted);
-  EXPECT_EQ(UPB_UPCAST(promoted),
-            upb_Message_GetMessage(msg, submsg_field, nullptr));
+  EXPECT_EQ(UPB_UPCAST(promoted), upb_Message_GetMessage(msg, submsg_field));
 
   // The repeated field should have two entries for the two parses.
   size_t repeated_size;
@@ -489,12 +487,10 @@
                  kUpb_DecodeOption_ExperimentalAllowUnlinked, arena.ptr());
   EXPECT_EQ(decode_status, kUpb_DecodeStatus_Ok);
   upb_test_ModelWithExtensions* promoted =
-      (upb_test_ModelWithExtensions*)upb_Message_GetMessage(msg, submsg_field,
-                                                            nullptr);
+      (upb_test_ModelWithExtensions*)upb_Message_GetMessage(msg, submsg_field);
 
   EXPECT_NE(nullptr, promoted);
-  EXPECT_EQ(UPB_UPCAST(promoted),
-            upb_Message_GetMessage(msg, submsg_field, nullptr));
+  EXPECT_EQ(UPB_UPCAST(promoted), upb_Message_GetMessage(msg, submsg_field));
 
   // The repeated field should have two entries for the two parses.
   size_t repeated_size;
@@ -737,8 +733,8 @@
           msg, mini_table, upb_MiniTable_GetFieldByIndex(mini_table, 1),
           &upb_0test__ModelWithExtensions_msg_init, decode_options, arena);
   EXPECT_EQ(promote_result.status, kUpb_UnknownToMessage_Ok);
-  const upb_Message* promoted_message = upb_Message_GetMessage(
-      msg, upb_MiniTable_GetFieldByIndex(mini_table, 1), nullptr);
+  const upb_Message* promoted_message =
+      upb_Message_GetMessage(msg, upb_MiniTable_GetFieldByIndex(mini_table, 1));
   EXPECT_EQ(upb_test_ModelWithExtensions_random_int32(
                 (upb_test_ModelWithExtensions*)promoted_message),
             12);