[CHERRY-PICK] Suppress FieldDoesNotExist raised from attribute on c…

…lass definition

If we've found an attribute on a model class that from all we can see
appears to be a field, but Django still raises `FieldDoesNotExist` we'll
suppress it.

This can appear if one uses the (undocumented) `Field(name=..., ...)`
argument.

mypy_django_plugin/transformers/fields.py

@@ -1,5 +1,6 @@
 from typing import TYPE_CHECKING, Any, Optional, Tuple, Union, cast
 
+from django.core.exceptions import FieldDoesNotExist
 from django.db.models.fields import AutoField, Field
 from django.db.models.fields.related import RelatedField
 from django.db.models.fields.reverse_related import ForeignObjectRel
@@ -38,8 +39,10 @@ def _get_current_field_from_assignment(
     if model_cls is None:
         return None
 
-    current_field = model_cls._meta.get_field(field_name)
-    return current_field
+    try:
+        return model_cls._meta.get_field(field_name)
+    except FieldDoesNotExist:
+        return None
 
 
 def reparametrize_related_field_type(related_field_type: Instance, set_type: MypyType, get_type: MypyType) -> Instance:

tests/typecheck/fields/test_base.yml

@@ -180,3 +180,24 @@
         obj = MyModel()
 
         reveal_type(obj.small) # N: Revealed type is "builtins.int"
+
+- case: test_ignores_renamed_field
+  main: |
+        # Ref: https://github.com/typeddjango/django-stubs/issues/1261
+        # Django modifies the model so it doesn't have 'modelname', but we don't follow
+        # along. But the 'name=' argument to a field isn't a documented feature.
+        from myapp.models import RenamedField
+        instance = RenamedField()
+        reveal_type(instance.modelname) # N: Revealed type is "builtins.int"
+        instance.fieldname # E: "RenamedField" has no attribute "fieldname"
+        instance.modelname = 1
+        instance.fieldname = 1 # E: "RenamedField" has no attribute "fieldname"
+  installed_apps:
+    - myapp
+  files:
+    - path: myapp/__init__.py
+    - path: myapp/models.py
+      content: |
+        from django.db import models
+        class RenamedField(models.Model):
+            modelname = models.IntegerField(name="fieldname", choices=((1, 'One'),))