Type get_response with a callback protocol.

Otherwise, calling `self.get_response(request)` in a subclass of `MiddlewareMixin` runs into `Invalid self argument` error. This is a workaround for python/mypy#5485. Signed-off-by: Zixuan James Li <[email protected]>
PIG208 · Aug 10, 2022 · 3d71af0 · 3d71af0
1 parent 99a6cef
commit 3d71af0
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diff --git a/django-stubs/utils/deprecation.pyi b/django-stubs/utils/deprecation.pyi
@@ -28,7 +28,7 @@ class DeprecationInstanceCheck(type):
     def __instancecheck__(self, instance: Any): ...
 
 class GetResponseCallable(Protocol):
-    def __call__(request: HttpRequest) -> HttpResponse: ...
+    def __call__(self, __request: HttpRequest) -> HttpResponse: ...
 
 class MiddlewareMixin:
     get_response: GetResponseCallable = ...

diff --git a/mypy_django_plugin/transformers/functional.py b/mypy_django_plugin/transformers/functional.py
@@ -26,9 +26,10 @@ def resolve_str_promise_attribute(ctx: AttributeContext) -> MypyType:
         return AnyType(TypeOfAny.from_error)
 
     if isinstance(method.type, CallableType):
-        # The proxied str methods are only meant to be used as instance methods.
+        if method.type.arg_names[0] != "self":
+            return method.type
+        # The proxied str methods are meant to be used as instance methods.
         # We need to drop the first `self` argument in them.
-        assert method.type.arg_names[0] == "self"
         return method.type.copy_modified(
             arg_kinds=method.type.arg_kinds[1:],
             arg_names=method.type.arg_names[1:],