WIP: django_stubs_ext: monkeypatch reveal_{type,locals} into builtins (#591)

* WIP: django_stubs_ext: monkeypatch `reveal_{type,locals}` into builtins

Fixes https://github.com/typeddjango/django-stubs/issues/590

* fixup! WIP: django_stubs_ext: monkeypatch `reveal_{type,locals}` into builtins

* fixup! fixup! WIP: django_stubs_ext: monkeypatch `reveal_{type,locals}` into builtins

* Update patch.py

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

django_stubs_ext/django_stubs_ext/patch.py

@@ -1,3 +1,4 @@
+import builtins
 from typing import Any, Generic, List, Optional, Tuple, Type, TypeVar
 
 from django import VERSION as VERSION
@@ -46,9 +47,10 @@ _need_generic: List[MPGeneric[Any]] = [
 ]
 
 
-# currently just adds the __class_getitem__ dunder. if more monkeypatching is needed, add it here
 def monkeypatch() -> None:
     """Monkey patch django as necessary to work properly with mypy."""
+
+    # Add the __class_getitem__ dunder.
     suited_for_this_version = filter(
         lambda spec: spec.version is None or VERSION[:2] <= spec.version,
         _need_generic,
@@ -56,5 +58,9 @@ def monkeypatch() -> None:
     for el in suited_for_this_version:
         el.cls.__class_getitem__ = classmethod(lambda cls, *args, **kwargs: cls)
 
+    # Define mypy builtins, to not cause NameError during setting up Django.
+    builtins.reveal_type = lambda _: None
+    builtins.reveal_locals = lambda: None
+
 
 __all__ = ["monkeypatch"]

django_stubs_ext/tests/test_monkeypatching.py

@@ -1,3 +1,4 @@
+import builtins
 from contextlib import suppress
 from typing import Optional
 
@@ -28,6 +29,9 @@ def make_generic_classes(
             with suppress(AttributeError):
                 delattr(el.cls, "__class_getitem__")
 
+        del builtins.reveal_type
+        del builtins.reveal_locals
+
     def factory(django_version: Optional[_VersionSpec] = None) -> None:
         if django_version is not None:
             monkeypatch.setattr(patch, "VERSION", django_version)
@@ -65,3 +69,12 @@ def test_patched_version_specific(
     for el in _need_generic:
         if el.version is not None and django_version <= el.version:
             assert el.cls[int] is el.cls
+
+
+def test_patched_mypy_builtins(make_generic_classes: _MakeGenericClasses) -> None:
+    make_generic_classes()
+
+    assert builtins.reveal_type
+    assert builtins.reveal_locals
+
+    reveal_type(reveal_locals)  # noqa: F821