allow field_serializer('*') (fix #8990) (#9001)

Co-authored-by: ornariece <37-ornariece@users.noreply.git.malined.com>
Co-authored-by: Sydney Runkle <54324534+sydney-runkle@users.noreply.github.com>

docs/concepts/serialization.md

@@ -224,6 +224,9 @@ print(Model(x='test value').model_dump_json())
 #> {"x":"serialized test value"}
 ```
 
+!!! note
+    A single serializer can also be called on all fields by passing the special value '*' to the [`@field_serializer`][pydantic.functional_serializers.field_serializer] decorator.
+
 In addition, [`PlainSerializer`][pydantic.functional_serializers.PlainSerializer] and
 [`WrapSerializer`][pydantic.functional_serializers.WrapSerializer] enable you to use a function to modify the output of serialization.
 

pydantic/_internal/_generate_schema.py

@@ -125,9 +125,8 @@ def check_validator_fields_against_field_name(
     Returns:
         `True` if field name is in validator fields, `False` otherwise.
     """
-    if isinstance(info, (ValidatorDecoratorInfo, FieldValidatorDecoratorInfo)):
-        if '*' in info.fields:
-            return True
+    if '*' in info.fields:
+        return True
     for v_field_name in info.fields:
         if v_field_name == field:
             return True
@@ -148,7 +147,7 @@ def check_decorator_fields_exist(decorators: Iterable[AnyFieldDecorator], fields
     """
     fields = set(fields)
     for dec in decorators:
-        if isinstance(dec.info, (ValidatorDecoratorInfo, FieldValidatorDecoratorInfo)) and '*' in dec.info.fields:
+        if '*' in dec.info.fields:
             continue
         if dec.info.check_fields is False:
             continue

tests/test_serialize.py

@@ -560,6 +560,18 @@ def serializer1(v) -> str:
     assert MySubModel(x=1234).model_dump() == {'x': '1234'}
 
 
+def test_serialize_all_fields():
+    class MyModel(BaseModel):
+        x: int
+
+        @field_serializer('*')
+        @classmethod
+        def serialize_all(cls, v: Any):
+            return v * 2
+
+    assert MyModel(x=10).model_dump() == {'x': 20}
+
+
 def int_ser_func_without_info1(v: int, expected: int) -> str:
     return f'{v:,}'
 

tests/test_validators.py

@@ -842,6 +842,18 @@ def check_a_two(cls, v: Any):
         Child(a='snap')
 
 
+def test_validate_all():
+    class MyModel(BaseModel):
+        x: int
+
+        @field_validator('*')
+        @classmethod
+        def validate_all(cls, v: Any):
+            return v * 2
+
+    assert MyModel(x=10).x == 20
+
+
 def test_validate_child_all():
     with pytest.warns(PydanticDeprecatedSince20, match=V1_VALIDATOR_DEPRECATION_MATCH):
 
@@ -861,6 +873,22 @@ def check_a(cls, v: Any):
         with pytest.raises(ValidationError):
             Child(a='snap')
 
+    class Parent(BaseModel):
+        a: str
+
+    class Child(Parent):
+        @field_validator('*')
+        @classmethod
+        def check_a(cls, v: Any):
+            if 'foobar' not in v:
+                raise ValueError('"foobar" not found in a')
+            return v
+
+    assert Parent(a='this is not a child').a == 'this is not a child'
+    assert Child(a='this is foobar good').a == 'this is foobar good'
+    with pytest.raises(ValidationError):
+        Child(a='snap')
+
 
 def test_validate_parent():
     class Parent(BaseModel):
@@ -907,6 +935,26 @@ class Child(Parent):
         with pytest.raises(ValidationError):
             Child(a='snap')
 
+    class Parent(BaseModel):
+        a: str
+
+        @field_validator('*')
+        @classmethod
+        def check_a(cls, v: Any):
+            if 'foobar' not in v:
+                raise ValueError('"foobar" not found in a')
+            return v
+
+    class Child(Parent):
+        pass
+
+    assert Parent(a='this is foobar good').a == 'this is foobar good'
+    assert Child(a='this is foobar good').a == 'this is foobar good'
+    with pytest.raises(ValidationError):
+        Parent(a='snap')
+    with pytest.raises(ValidationError):
+        Child(a='snap')
+
 
 def test_inheritance_keep():
     class Parent(BaseModel):