Disable monkeypatches, add dependencies via new hook (#60)

* code cleanups, disable monkeypatches, move to add_additional_deps

* disable incremental mode for tests

* add pip-wheel-metadata

* move some code from get_base_hook to get_attribute_hook to reduce dependencies

* simplify values/values_list tests and code

* disable cache for some tests failing with incremental mode

* enable incremental mode for tests typechecking

* pin mypy version

* fix tests

* lint

* fix internal crashes

mypy_django_plugin/transformers/forms.py

@@ -1,4 +1,5 @@
-from mypy.plugin import ClassDefContext
+from mypy.plugin import ClassDefContext, MethodContext
+from mypy.types import CallableType, Instance, NoneTyp, Type, TypeType
 
 from mypy_django_plugin import helpers
 
@@ -8,3 +9,38 @@ def make_meta_nested_class_inherit_from_any(ctx: ClassDefContext) -> None:
     if meta_node is None:
         return None
     meta_node.fallback_to_any = True
+
+
+def extract_proper_type_for_get_form(ctx: MethodContext) -> Type:
+    object_type = ctx.type
+    if not isinstance(object_type, Instance):
+        return ctx.default_return_type
+
+    form_class_type = helpers.get_argument_type_by_name(ctx, 'form_class')
+    if form_class_type is None or isinstance(form_class_type, NoneTyp):
+        # extract from specified form_class in metadata
+        form_class_fullname = helpers.get_django_metadata(object_type.type).get('form_class', None)
+        if not form_class_fullname:
+            return ctx.default_return_type
+
+        return ctx.api.named_generic_type(form_class_fullname, [])
+
+    if isinstance(form_class_type, TypeType) and isinstance(form_class_type.item, Instance):
+        return form_class_type.item
+
+    if isinstance(form_class_type, CallableType) and isinstance(form_class_type.ret_type, Instance):
+        return form_class_type.ret_type
+
+    return ctx.default_return_type
+
+
+def extract_proper_type_for_get_form_class(ctx: MethodContext) -> Type:
+    object_type = ctx.type
+    if not isinstance(object_type, Instance):
+        return ctx.default_return_type
+
+    form_class_fullname = helpers.get_django_metadata(object_type.type).get('form_class', None)
+    if not form_class_fullname:
+        return ctx.default_return_type
+
+    return TypeType(ctx.api.named_generic_type(form_class_fullname, []))