Fixed #27914 -- Added support for nested classes in Field.deconstruct()/__repr__().

django/db/models/fields/__init__.py

@@ -191,7 +191,7 @@ class Field(RegisterLookupMixin):
 
     def __repr__(self):
         """Display the module, class, and name of the field."""
-        path = '%s.%s' % (self.__class__.__module__, self.__class__.__name__)
+        path = '%s.%s' % (self.__class__.__module__, self.__class__.__qualname__)
         name = getattr(self, 'name', None)
         if name is not None:
             return '<%s: %s>' % (path, name)
@@ -448,7 +448,7 @@ class Field(RegisterLookupMixin):
                 if value is not default:
                     keywords[name] = value
         # Work out path - we shorten it for known Django core fields
-        path = "%s.%s" % (self.__class__.__module__, self.__class__.__name__)
+        path = "%s.%s" % (self.__class__.__module__, self.__class__.__qualname__)
         if path.startswith("django.db.models.fields.related"):
             path = path.replace("django.db.models.fields.related", "django.db.models")
         if path.startswith("django.db.models.fields.files"):

tests/model_fields/tests.py

@@ -9,6 +9,11 @@ from .models import (
 )
 
 
+class Nested():
+    class Field(models.Field):
+        pass
+
+
 class BasicFieldTests(TestCase):
 
     def test_show_hidden_initial(self):
@@ -33,6 +38,10 @@ class BasicFieldTests(TestCase):
         f = models.fields.CharField()
         self.assertEqual(repr(f), '<django.db.models.fields.CharField>')
 
+    def test_field_repr_nested(self):
+        """__repr__() uses __qualname__ for nested class support."""
+        self.assertEqual(repr(Nested.Field()), '<model_fields.tests.Nested.Field>')
+
     def test_field_name(self):
         """
         A defined field name (name="fieldname") is used instead of the model
@@ -85,6 +94,11 @@ class BasicFieldTests(TestCase):
         field._get_default
         pickle.dumps(field)
 
+    def test_deconstruct_nested_field(self):
+        """deconstruct() uses __qualname__ for nested class support."""
+        name, path, args, kwargs = Nested.Field().deconstruct()
+        self.assertEqual(path, 'model_fields.tests.Nested.Field')
+
 
 class ChoicesTests(SimpleTestCase):