Support __get_validators__ (#7197)

pydantic/_internal/_generate_schema.py

@@ -587,16 +587,25 @@ def _generate_schema_from_property(self, obj: Any, source: Any) -> core_schema.C
         else:
             ref_mode = 'to-def'
 
+        schema: CoreSchema
         get_schema = getattr(obj, '__get_pydantic_core_schema__', None)
         if get_schema is None:
-            return None
-
-        schema: CoreSchema
-        if len(inspect.signature(get_schema).parameters) == 1:
-            # (source) -> CoreSchema
-            schema = get_schema(source)
+            validators = getattr(obj, '__get_validators__', None)
+            if validators is None:
+                return None
+            warn(
+                '`__get_validators__` is deprecated and will be removed, use `__get_pydantic_core_schema__` instead.',
+                PydanticDeprecatedSince20,
+            )
+            schema = core_schema.chain_schema([core_schema.general_plain_validator_function(v) for v in validators()])
         else:
-            schema = get_schema(source, CallbackGetCoreSchemaHandler(self._generate_schema, self, ref_mode=ref_mode))
+            if len(inspect.signature(get_schema).parameters) == 1:
+                # (source) -> CoreSchema
+                schema = get_schema(source)
+            else:
+                schema = get_schema(
+                    source, CallbackGetCoreSchemaHandler(self._generate_schema, self, ref_mode=ref_mode)
+                )
 
         schema = self._unpack_refs_defs(schema)
 

tests/test_deprecated.py

@@ -1,7 +1,7 @@
 import platform
 import re
 import sys
-from datetime import timedelta
+from datetime import date, timedelta
 from pathlib import Path
 from types import SimpleNamespace
 from typing import Any, Dict, Iterable, List, Type
@@ -523,6 +523,62 @@ def __get_validators__(cls) -> Iterable[Any]:
     assert ta.json_schema() == {'anyOf': [{'type': 'string'}, {'type': 'number'}]}
 
 
+def test_v1_get_validators():
+    class CustomDate(date):
+        @classmethod
+        def __get_validators__(cls):
+            yield cls.validate1
+            yield cls.validate2
+
+        @classmethod
+        def validate1(cls, v, i):
+            print(v)
+
+            if v.year < 2000:
+                raise ValueError('Invalid year')
+            return v
+
+        @classmethod
+        def validate2(cls, v, i):
+            return date.today().replace(month=1, day=1)
+
+    with pytest.warns(
+        PydanticDeprecatedSince20,
+        match='^`__get_validators__` is deprecated and will be removed, use `__get_pydantic_core_schema__` instead.',
+    ):
+
+        class Model(BaseModel):
+            x: CustomDate
+
+    with pytest.raises(ValidationError, match='Value error, Invalid year'):
+        Model(x=date(1999, 1, 1))
+
+    m = Model(x=date.today())
+    assert m.x.day == 1
+
+
+def test_v1_get_validators_invalid_validator():
+    class InvalidValidator:
+        @classmethod
+        def __get_validators__(cls):
+            yield cls.has_wrong_arguments
+
+        @classmethod
+        def has_wrong_arguments(cls):
+            pass
+
+    with pytest.warns(
+        PydanticDeprecatedSince20,
+        match='^`__get_validators__` is deprecated and will be removed, use `__get_pydantic_core_schema__` instead.',
+    ):
+
+        class InvalidValidatorModel(BaseModel):
+            x: InvalidValidator
+
+    with pytest.raises(TypeError, match='takes 1 positional argument but 3 were given'):
+        InvalidValidatorModel(x=1)
+
+
 def test_field_extra_arguments():
     m = re.escape(
         'Using extra keyword arguments on `Field` is deprecated and will be removed. Use `json_schema_extra` instead. '

tests/test_edge_cases.py

@@ -1504,13 +1504,6 @@ def __init__(self, t1: T1, t2: T2):
         self.t1 = t1
         self.t2 = t2
 
-    @classmethod
-    def __get_validators__(cls):
-        def validator(v):
-            return v
-
-        yield validator
-
 
 @pytest.mark.parametrize(
     'type_,expected',