Minor fix for autocreated object repeated fields and maps.

- If setting/clearing a repeated field/map that was objects, check the class
  before checking the autocreator.
- Just to be paranoid, don’t mutate within copy/mutableCopy for the autocreated
  classes to ensure there is less chance of issues if someone does something
  really crazy threading wise.
- Some more tests for the internal AutocreatedArray/AutocreatedDictionary
  classes to ensure things are working as expected.
- Add Xcode 8.2 to the full_mac_build.sh supported list.

1 files changed, 10 insertions, 6 deletions

diff --git a/objectivec/GPBMessage.m b/objectivec/GPBMessage.m
index 4a6f0612..9660f1ed 100644
--- a/objectivec/GPBMessage.m
+++ b/objectivec/GPBMessage.m
@@ -1023,9 +1023,11 @@ static GPBUnknownFieldSet *GetOrMakeUnknownFields(GPBMessage *self) {
       if (arrayOrMap) {
         if (field.fieldType == GPBFieldTypeRepeated) {
           if (GPBFieldDataTypeIsObject(field)) {
-            GPBAutocreatedArray *autoArray = arrayOrMap;
-            if (autoArray->_autocreator == self) {
-              autoArray->_autocreator = nil;
+            if ([arrayOrMap isKindOfClass:[GPBAutocreatedArray class]]) {
+              GPBAutocreatedArray *autoArray = arrayOrMap;
+              if (autoArray->_autocreator == self) {
+                autoArray->_autocreator = nil;
+              }
             }
           } else {
             // Type doesn't matter, it is a GPB*Array.
@@ -1037,9 +1039,11 @@ static GPBUnknownFieldSet *GetOrMakeUnknownFields(GPBMessage *self) {
         } else {
           if ((field.mapKeyDataType == GPBDataTypeString) &&
               GPBFieldDataTypeIsObject(field)) {
-            GPBAutocreatedDictionary *autoDict = arrayOrMap;
-            if (autoDict->_autocreator == self) {
-              autoDict->_autocreator = nil;
+            if ([arrayOrMap isKindOfClass:[GPBAutocreatedDictionary class]]) {
+              GPBAutocreatedDictionary *autoDict = arrayOrMap;
+              if (autoDict->_autocreator == self) {
+                autoDict->_autocreator = nil;
+              }
             }
           } else {
             // Type doesn't matter, it is a GPB*Dictionary.