Addressed PR comments.

python/message.c

@@ -989,9 +989,8 @@ PyObject* PyUpb_CMessage_MergeFromString(PyObject* _self, PyObject* arg) {
   const upb_extreg* extreg = upb_symtab_extreg(upb_filedef_symtab(file));
   const upb_msglayout* layout = upb_msgdef_layout(msgdef);
   upb_arena* arena = PyUpb_Arena_Get(self->arena);
-  int options = 0;
   PyUpb_ModuleState* state = PyUpb_ModuleState_Get();
-  options |=
+  int options =
       UPB_DECODE_MAXDEPTH(state->allow_oversize_protos ? UINT32_MAX : 100);
   upb_DecodeStatus status =
       _upb_decode(buf, size, self->ptr.msg, layout, extreg, options, arena);
@@ -1186,11 +1185,10 @@ PyObject* PyUpb_CMessage_SerializeInternal(PyObject* _self, PyObject* args,
   const upb_msgdef* msgdef = _PyUpb_CMessage_GetMsgdef(self);
   const upb_msglayout* layout = upb_msgdef_layout(msgdef);
   size_t size = 0;
-  int options = 0;
+  int options = UPB_ENCODE_MAXDEPTH(UINT32_MAX);
   if (check_required) options |= UPB_ENCODE_CHECKREQUIRED;
   if (deterministic) options |= UPB_ENCODE_DETERMINISTIC;
   // Python does not currently have any effective limit on serialization depth.
-  options |= UPB_ENCODE_MAXDEPTH(UINT32_MAX);
   char* pb = upb_encode_ex(self->ptr.msg, layout, options, arena, &size);
   PyObject* ret = NULL;
 

upb/msg.c

@@ -252,34 +252,36 @@ static void _upb_mapsorter_getkeys(const void *_a, const void *_b, void *a_key,
   _upb_map_fromkey(b_tabkey, b_key, size);
 }
 
+#define COMPARE_INTEGERS(a, b) ((a) < (b) ? -1 : ((a) == (b) ? 0 : 1))
+
 static int _upb_mapsorter_cmpi64(const void *_a, const void *_b) {
   int64_t a, b;
   _upb_mapsorter_getkeys(_a, _b, &a, &b, 8);
-  return a - b;
+  return COMPARE_INTEGERS(a, b);
 }
 
 static int _upb_mapsorter_cmpu64(const void *_a, const void *_b) {
   uint64_t a, b;
   _upb_mapsorter_getkeys(_a, _b, &a, &b, 8);
-  return a - b;
+  return COMPARE_INTEGERS(a, b);
 }
 
 static int _upb_mapsorter_cmpi32(const void *_a, const void *_b) {
   int32_t a, b;
   _upb_mapsorter_getkeys(_a, _b, &a, &b, 4);
-  return a - b;
+  return COMPARE_INTEGERS(a, b);
 }
 
 static int _upb_mapsorter_cmpu32(const void *_a, const void *_b) {
   uint32_t a, b;
   _upb_mapsorter_getkeys(_a, _b, &a, &b, 4);
-  return a - b;
+  return COMPARE_INTEGERS(a, b);
 }
 
 static int _upb_mapsorter_cmpbool(const void *_a, const void *_b) {
   bool a, b;
   _upb_mapsorter_getkeys(_a, _b, &a, &b, 1);
-  return a - b;
+  return COMPARE_INTEGERS(a, b);
 }
 
 static int _upb_mapsorter_cmpstr(const void *_a, const void *_b) {
@@ -288,9 +290,11 @@ static int _upb_mapsorter_cmpstr(const void *_a, const void *_b) {
   size_t common_size = UPB_MIN(a.size, b.size);
   int cmp = memcmp(a.data, b.data, common_size);
   if (cmp) return -cmp;
-  return a.size - b.size;
+  return COMPARE_INTEGERS(a.size, b.size);
 }
 
+#undef COMPARE_INTEGERS
+
 bool _upb_mapsorter_pushmap(_upb_mapsorter *s, upb_descriptortype_t key_type,
                             const upb_map *map, _upb_sortedmap *sorted) {
   int map_size = _upb_map_size(map);