Error during parsing for invalid UTF-8 instead of dropping dropping data.

This seems to be some code evolution side effects. Back when there was a custom
string class, we couldn't really error when we finally saw the string was bad
so we had to return the empty string, but now that full validation is done
up front, it can error out.

2 files changed, 9 insertions, 9 deletions

diff --git a/objectivec/GPBCodedInputStream.m b/objectivec/GPBCodedInputStream.m
index eaa28e50..319ec15b 100644
--- a/objectivec/GPBCodedInputStream.m
+++ b/objectivec/GPBCodedInputStream.m
@@ -219,15 +219,16 @@ NSString *GPBCodedInputStreamReadRetainedString(
     result = [[NSString alloc] initWithBytes:&state->bytes[state->bufferPos]
                                       length:size
                                     encoding:NSUTF8StringEncoding];
+    state->bufferPos += size;
     if (!result) {
-      result = @"";
 #ifdef DEBUG
       // https://developers.google.com/protocol-buffers/docs/proto#scalar
-      NSLog(@"UTF8 failure, is some field type 'string' when it should be "
+      NSLog(@"UTF-8 failure, is some field type 'string' when it should be "
             @"'bytes'?");
 #endif
+      [NSException raise:NSParseErrorException
+                  format:@"Invalid UTF-8 for a 'string'"];
     }
-    state->bufferPos += size;
   }
   return result;
 }
diff --git a/objectivec/Tests/GPBCodedInputStreamTests.m b/objectivec/Tests/GPBCodedInputStreamTests.m
index b40360eb..cc402156 100644
--- a/objectivec/Tests/GPBCodedInputStreamTests.m
+++ b/objectivec/Tests/GPBCodedInputStreamTests.m
@@ -283,16 +283,15 @@
   [output writeRawData:[NSData dataWithBytes:bytes length:sizeof(bytes)]];
   [output flush];
 
-  NSData* data =
+  NSData *data =
       [rawOutput propertyForKey:NSStreamDataWrittenToMemoryStreamKey];
   GPBCodedInputStream* input = [GPBCodedInputStream streamWithData:data];
+  NSError *error = nil;
   TestAllTypes* message = [TestAllTypes parseFromCodedInputStream:input
                                                 extensionRegistry:nil
-                                                            error:NULL];
-  XCTAssertNotNil(message);
-  // Make sure we can read string properties twice without crashing.
-  XCTAssertEqual([message.defaultString length], (NSUInteger)0);
-  XCTAssertEqualObjects(@"", message.defaultString);
+                                                            error:&error];
+  XCTAssertNotNil(error);
+  XCTAssertNil(message);
 }
 
 - (void)testBOMWithinStrings {