Add test for functoool.partial validators

pydantic/class_validators.py

@@ -1,6 +1,6 @@
 import warnings
 from collections import ChainMap
-from functools import wraps
+from functools import partial, partialmethod, wraps
 from itertools import chain
 from types import FunctionType
 from typing import TYPE_CHECKING, Any, Callable, Dict, Iterable, List, Optional, Set, Tuple, Type, Union, overload
@@ -145,6 +145,8 @@ def _prepare_validator(function: AnyCallable, allow_reuse: bool) -> 'AnyClassMet
     Avoid validators with duplicated names since without this, validators can be overwritten silently
     which generally isn't the intended behaviour, don't run in ipython (see #312) or if allow_reuse is False.
     """
+    if isinstance(function, (partial, partialmethod)):
+        raise ConfigError('validators created using `functools` are not supported')
     f_cls = function if isinstance(function, classmethod) else classmethod(function)
     if not in_ipython() and not allow_reuse:
         ref = f_cls.__func__.__module__ + '.' + f_cls.__func__.__qualname__

tests/test_validators.py

@@ -1,8 +1,9 @@
 from collections import deque
 from datetime import datetime
 from enum import Enum
+from functools import partial, partialmethod
 from itertools import product
-from typing import Dict, List, Optional, Tuple, Union
+from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
 import pytest
 from typing_extensions import Literal
@@ -1345,3 +1346,33 @@ class Model(BaseModel):
         {'loc': ('foo',), 'msg': 'the list has duplicated items', 'type': 'value_error.list.unique_items'},
         {'loc': ('bar',), 'msg': 'the list has duplicated items', 'type': 'value_error.list.unique_items'},
     ]
+
+
+@pytest.mark.parametrize(
+    'func,allow_reuse',
+    [
+        pytest.param(partial, False, id='`partial` and check for reuse'),
+        pytest.param(partial, True, id='`partial` and ignore reuse'),
+        pytest.param(partialmethod, False, id='`partialmethod` and check for reuse'),
+        pytest.param(partialmethod, False, id='`partialmethod` and ignore reuse'),
+    ],
+)
+def test_functool_as_validator(
+    func: Callable,
+    allow_reuse: bool,
+):
+    def custom_validator(
+        cls,
+        v: Any,
+        allowed: str,
+    ) -> Any:
+        assert v == allowed, f'Only {allowed} allowed as value; given: {v}'
+        return v
+
+    validate = func(custom_validator, allowed='TEXT')
+
+    with pytest.raises(ConfigError, match='validators created using `functools` are not supported'):
+
+        class TestClass(BaseModel):
+            name: str
+            _custom_validate = validator('name', allow_reuse=allow_reuse)(validate)