[FIX] pydantic: Makes issubclass on BaseModel working with generics

pydantic/__manifest__.py

@@ -15,10 +15,7 @@
     "data": [],
     "demo": [],
     "external_dependencies": {
-        "python": [
-            "pydantic",
-            "contextvars",
-        ]
+        "python": ["pydantic", "contextvars", "typing-extensions>=4.0.1"]
     },
     "installable": True,
 }

pydantic/models.py

@@ -151,7 +151,7 @@ def __subclasscheck__(cls, subclass):  # noqa: B902
         """Implement issubclass(sub, cls)."""
         if hasattr(subclass, "_original_cls"):
             return cls.__subclasscheck__(subclass._original_cls)
-        return super().__subclasscheck__(subclass)
+        return isinstance(subclass, type) and super().__subclasscheck__(subclass)
 
 
 class BaseModel(pydantic.BaseModel, metaclass=ExtendablePydanticModelMeta):

pydantic/tests/test_pydantic.py

@@ -3,6 +3,11 @@
 
 from typing import List
 
+try:
+    from typing import Literal
+except ImportError:
+    from typing_extensions import Literal
+
 import pydantic
 
 from .. import models, utils
@@ -154,3 +159,18 @@ class ExtendedLocation(Location, extends=Location):
         inst2 = ExtendedLocation.construct()
         self.assertEqual(inst1.__class__, inst2.__class__)
         self.assertEqual(inst1.schema(), inst2.schema())
+
+    def test_issubclass(self):
+        """In this test we check that issublass is lenient when used with
+        GenericAlias
+        """
+        self.assertFalse(issubclass(Literal["test"], models.BaseModel))
+        self.assertFalse(issubclass(Literal, models.BaseModel))
+
+        class Location(models.BaseModel):
+            kind: Literal["view", "bin"]
+            my_list: List[str]
+
+        self._build_pydantic_classes(Location)
+        schema = Location.schema()
+        self.assertTrue(schema)

requirements.txt

@@ -9,3 +9,4 @@ marshmallow-objects>=2.0.0
 parse-accept-language
 pydantic
 pyquerystring
+typing-extensions>=4.0.1