Add nonnil markup to ObjC library.

Add the clang annotations to the objc library and generated code to help with Swift bridging and compiler checks.

1 files changed, 2 insertions, 2 deletions

diff --git a/objectivec/GPBUtilities.m b/objectivec/GPBUtilities.m
index 7a035ce6..5ee61230 100644
--- a/objectivec/GPBUtilities.m
+++ b/objectivec/GPBUtilities.m
@@ -1497,7 +1497,7 @@ static void AppendTextFormatForMessage(GPBMessage *message,
 }
 
 NSString *GPBTextFormatForMessage(GPBMessage *message, NSString *lineIndent) {
-  if (message == nil) return nil;
+  if (message == nil) return @"";
   if (lineIndent == nil) lineIndent = @"";
 
   NSMutableString *buildString = [NSMutableString string];
@@ -1507,7 +1507,7 @@ NSString *GPBTextFormatForMessage(GPBMessage *message, NSString *lineIndent) {
 
 NSString *GPBTextFormatForUnknownFieldSet(GPBUnknownFieldSet *unknownSet,
                                           NSString *lineIndent) {
-  if (unknownSet == nil) return nil;
+  if (unknownSet == nil) return @"";
   if (lineIndent == nil) lineIndent = @"";
 
   NSMutableString *result = [NSMutableString string];