move meta to new API

Author: mkurnikov

mypy_django_plugin/lib/helpers.py

@@ -185,11 +185,13 @@ def lookup_typeinfo(self, fullname: str) -> Optional[TypeInfo]:
 
 class GetMethodCallback(TypeCheckerPluginCallback):
     ctx: MethodContext
+    callee_type: Instance
     default_return_type: MypyType
 
     def __call__(self, ctx: MethodContext) -> MypyType:
         self.type_checker = cast(TypeChecker, ctx.api)
         self.ctx = ctx
+        self.callee_type = cast(Instance, ctx.type)
         self.default_return_type = self.ctx.default_return_type
         return self.get_method_return_type()
 

mypy_django_plugin/main.py

@@ -14,11 +14,12 @@
 import mypy_django_plugin.transformers.orm_lookups
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.lib import fullnames, helpers
-from mypy_django_plugin.transformers import init_create, meta, querysets
+from mypy_django_plugin.transformers import init_create, querysets
 from mypy_django_plugin.transformers2.fields import FieldContructorCallback
 from mypy_django_plugin.transformers2.forms import (
     FormCallback, GetFormCallback, GetFormClassCallback,
 )
+from mypy_django_plugin.transformers2.meta import MetaGetFieldCallback
 from mypy_django_plugin.transformers2.models import ModelCallback
 from mypy_django_plugin.transformers2.related_managers import (
     GetRelatedManagerCallback,
@@ -198,7 +199,7 @@ def get_method_hook(self, fullname: str
         if method_name == 'get_field':
             info = self._get_typeinfo_or_none(class_fullname)
             if info and info.has_base(fullnames.OPTIONS_CLASS_FULLNAME):
-                return partial(meta.return_proper_field_type_from_get_field, django_context=self.django_context)
+                return MetaGetFieldCallback(self)
 
         manager_classes = self._get_current_manager_bases()
         if class_fullname in manager_classes and method_name == 'create':

mypy_django_plugin/transformers/meta.py

@@ -16,21 +16,18 @@ def modify_class_defn(self) -> None:
 
 
 class FormMethodCallback(helpers.GetMethodCallback):
-    def get_specified_form_class(self, object_type: Instance) -> Optional[TypeType]:
-        form_class_sym = object_type.type.get('form_class')
+    def get_specified_form_class(self) -> Optional[TypeType]:
+        form_class_sym = self.callee_type.type.get('form_class')
         if form_class_sym and isinstance(form_class_sym.type, CallableType):
             return TypeType(form_class_sym.type.ret_type)
         return None
 
 
 class GetFormCallback(FormMethodCallback):
     def get_method_return_type(self) -> MypyType:
-        object_type = self.ctx.type
-        assert isinstance(object_type, Instance)
-
         form_class_type = chk_helpers.get_call_argument_type_by_name(self.ctx, 'form_class')
         if form_class_type is None or isinstance(form_class_type, NoneTyp):
-            form_class_type = self.get_specified_form_class(object_type)
+            form_class_type = self.get_specified_form_class()
 
         if isinstance(form_class_type, TypeType) and isinstance(form_class_type.item, Instance):
             return form_class_type.item
@@ -43,10 +40,7 @@ def get_method_return_type(self) -> MypyType:
 
 class GetFormClassCallback(FormMethodCallback):
     def get_method_return_type(self) -> MypyType:
-        object_type = self.ctx.type
-        assert isinstance(object_type, Instance)
-
-        form_class_type = self.get_specified_form_class(object_type)
+        form_class_type = self.get_specified_form_class()
         if form_class_type is None:
             return self.default_return_type
 

mypy_django_plugin/transformers2/forms.py

@@ -0,0 +1,46 @@
+from django.core.exceptions import FieldDoesNotExist
+from mypy.types import AnyType, Instance
+from mypy.types import Type as MypyType
+from mypy.types import TypeOfAny
+
+from mypy_django_plugin.lib import chk_helpers, helpers
+
+
+class MetaGetFieldCallback(helpers.GetMethodCallback):
+    def _get_field_instance(self, field_fullname: str) -> MypyType:
+        field_info = helpers.lookup_fully_qualified_typeinfo(self.type_checker, field_fullname)
+        if field_info is None:
+            return AnyType(TypeOfAny.unannotated)
+        return Instance(field_info, [AnyType(TypeOfAny.explicit), AnyType(TypeOfAny.explicit)])
+
+    def get_method_return_type(self) -> MypyType:
+        # bail if list of generic params is empty
+        if len(self.callee_type.args) == 0:
+            return self.default_return_type
+
+        model_type = self.callee_type.args[0]
+        if not isinstance(model_type, Instance):
+            return self.default_return_type
+
+        model_cls = self.django_context.get_model_class_by_fullname(model_type.type.fullname)
+        if model_cls is None:
+            return self.default_return_type
+
+        field_name_expr = chk_helpers.get_call_argument_by_name(self.ctx, 'field_name')
+        if field_name_expr is None:
+            return self.default_return_type
+
+        field_name = helpers.resolve_string_attribute_value(field_name_expr, self.django_context)
+        if field_name is None:
+            return self.default_return_type
+
+        try:
+            field = model_cls._meta.get_field(field_name)
+        except FieldDoesNotExist as exc:
+            # if model is abstract, do not raise exception, skip false positives
+            if not model_cls._meta.abstract:
+                self.ctx.api.fail(exc.args[0], self.ctx.context)
+            return AnyType(TypeOfAny.from_error)
+
+        field_fullname = helpers.get_class_fullname(field.__class__)
+        return self._get_field_instance(field_fullname)