Intentionally break mixing the new and old type interfaces.

2 files changed, 33 insertions, 17 deletions

diff --git a/jsonschema/tests/test_validators.py b/jsonschema/tests/test_validators.py
index 4a25a28..5068627 100644
--- a/jsonschema/tests/test_validators.py
+++ b/jsonschema/tests/test_validators.py
@@ -165,22 +165,6 @@ class TestLegacyTypeCheckCreation(SynchronousTestCase):
 
         self.assertEqual(set(Validator.DEFAULT_TYPES), expected_types)
 
-    @unittest.skip("This logic is actually incorrect.")
-    def test_default_types_update_type_checker(self):
-        Validator = validators.create(
-            meta_schema=self.meta_schema,
-            validators=self.validators,
-            default_types={u"array": list}
-        )
-
-        self.assertEqual(set(Validator.DEFAULT_TYPES), {u"array"})
-        Extended = validators.extend(
-            Validator,
-            type_checker=Validator.TYPE_CHECKER.remove(u"array")
-        )
-
-        self.assertEqual(set(Extended.DEFAULT_TYPES), {})
-
     def test_types_redefines_the_validators_type_checker(self):
         schema = {"type": "string"}
         self.assertFalse(validators.Draft7Validator(schema).is_valid(12))
@@ -243,6 +227,29 @@ class TestLegacyTypeCheckingDeprecation(SynchronousTestCase):
         )
         self.assertFalse(self.flushWarnings())
 
+    def test_extending_a_legacy_validator_with_a_type_checker_errors(self):
+        Validator = validators.create(
+            meta_schema={},
+            validators={},
+            default_types={u"array": list}
+        )
+        with self.assertRaises(TypeError) as e:
+            validators.extend(
+                Validator,
+                validators={},
+                type_checker=TypeChecker(),
+            )
+
+        self.assertIn(
+            (
+                "Cannot extend a validator created with default_types "
+                "with a type_checker. Update the validator to use a "
+                "type_checker when created."
+            ),
+            str(e.exception),
+        )
+        self.flushWarnings()
+
     def test_extending_a_legacy_validator_does_not_rewarn(self):
         Validator = validators.create(meta_schema={}, default_types={})
         self.assertTrue(self.flushWarnings())
diff --git a/jsonschema/validators.py b/jsonschema/validators.py
index 90c0f1b..264a949 100644
--- a/jsonschema/validators.py
+++ b/jsonschema/validators.py
@@ -200,6 +200,7 @@ def create(
             raise TypeError(
                 "Do not specify default_types when providing a type checker.",
             )
+        _created_with_default_types = True
         warn(
             (
                 "The default_types argument is deprecated. "
@@ -213,6 +214,7 @@ def create(
         )
     else:
         default_types = _DEPRECATED_DEFAULT_TYPES
+        _created_with_default_types = False
         if type_checker is None:
             type_checker = _types.TypeChecker()
 
@@ -226,6 +228,7 @@ def create(
 
         DEFAULT_TYPES = property(_DEFAULT_TYPES)
         _DEFAULT_TYPES = dict(default_types)
+        _CREATED_WITH_DEFAULT_TYPES = _created_with_default_types
 
         def __init__(
             self,
@@ -393,8 +396,14 @@ def extend(validator, validators=(), version=None, type_checker=None):
     all_validators = dict(validator.VALIDATORS)
     all_validators.update(validators)
 
-    if not type_checker:
+    if type_checker is None:
         type_checker = validator.TYPE_CHECKER
+    elif validator._CREATED_WITH_DEFAULT_TYPES:
+        raise TypeError(
+            "Cannot extend a validator created with default_types "
+            "with a type_checker. Update the validator to use a "
+            "type_checker when created."
+        )
 
     # Set the default_types to None during class creation to avoid
     # overwriting the type checker (and triggering the deprecation warning).