bpo-38857: AsyncMock fix for awaitable values and StopIteration fix [3.8] (GH-17269)

Lib/unittest/mock.py

@@ -1139,8 +1139,8 @@ class CallableMixin(Base):
             _new_parent = _new_parent._mock_new_parent
 
     def _execute_mock_call(self, /, *args, **kwargs):
-        # seperate from _increment_mock_call so that awaited functions are
-        # executed seperately from their call
+        # separate from _increment_mock_call so that awaited functions are
+        # executed separately from their call, also AsyncMock overrides this method
 
         effect = self.side_effect
         if effect is not None:
@@ -2136,29 +2136,45 @@ class AsyncMockMixin(Base):
         code_mock.co_flags = inspect.CO_COROUTINE
         self.__dict__['__code__'] = code_mock
 
-    async def _mock_call(self, /, *args, **kwargs):
-        try:
-            result = super()._mock_call(*args, **kwargs)
-        except (BaseException, StopIteration) as e:
-            side_effect = self.side_effect
-            if side_effect is not None and not callable(side_effect):
-                raise
-            return await _raise(e)
+    async def _execute_mock_call(self, /, *args, **kwargs):
+        # This is nearly just like super(), except for sepcial handling
+        # of coroutines
 
         _call = self.call_args
+        self.await_count += 1
+        self.await_args = _call
+        self.await_args_list.append(_call)
 
-        async def proxy():
-            try:
-                if inspect.isawaitable(result):
-                    return await result
-                else:
-                    return result
-            finally:
-                self.await_count += 1
-                self.await_args = _call
-                self.await_args_list.append(_call)
+        effect = self.side_effect
+        if effect is not None:
+            if _is_exception(effect):
+                raise effect
+            elif not _callable(effect):
+                try:
+                    result = next(effect)
+                except StopIteration:
+                    # It is impossible to propogate a StopIteration
+                    # through coroutines because of PEP 479
+                    raise StopAsyncIteration
+                if _is_exception(result):
+                    raise result
+            elif asyncio.iscoroutinefunction(effect):
+                result = await effect(*args, **kwargs)
+            else:
+                result = effect(*args, **kwargs)
 
-        return await proxy()
+            if result is not DEFAULT:
+                return result
+
+        if self._mock_return_value is not DEFAULT:
+            return self.return_value
+
+        if self._mock_wraps is not None:
+            if asyncio.iscoroutinefunction(self._mock_wraps):
+                return await self._mock_wraps(*args, **kwargs)
+            return self._mock_wraps(*args, **kwargs)
+
+        return self.return_value
 
     def assert_awaited(self):
         """
@@ -2864,10 +2880,6 @@ def seal(mock):
             seal(m)
 
 
-async def _raise(exception):
-    raise exception
-
-
 class _AsyncIterator:
     """
     Wraps an iterator in an asynchronous iterator.