[cherry-pick] Fix mypy plugin for 1.1.0 (#5077) (#5111)

* Fix mypy plugin for 1.1.0 (#5077)

* Fix mypy plugin for 1.1.0
* Code review
* Add version key to plugin data

(cherry picked from commit 6267ae3)

* Change file name

* Add the changes from #5120

* Update changes file

* Remove additional unneeded dataclass import (from #5120)

---------

Co-authored-by: David Montague <35119617+dmontagu@users.noreply.github.com>

changes/5111-cdce8p.md

@@ -0,0 +1 @@
+Fix mypy plugin for v1.1.1, and fix `dataclass_transform` decorator for pydantic dataclasses

pydantic/dataclasses.py

@@ -32,6 +32,7 @@ class M:
 validation without altering default `M` behaviour.
 """
 import copy
+import dataclasses
 import sys
 from contextlib import contextmanager
 from functools import wraps
@@ -93,7 +94,7 @@ def __validate__(cls: Type['DataclassT'], v: Any) -> 'DataclassT':
 
 if sys.version_info >= (3, 10):
 
-    @dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+    @dataclass_transform(field_specifiers=(dataclasses.field, Field))
     @overload
     def dataclass(
         *,
@@ -110,7 +111,7 @@ def dataclass(
     ) -> Callable[[Type[_T]], 'DataclassClassOrWrapper']:
         ...
 
-    @dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+    @dataclass_transform(field_specifiers=(dataclasses.field, Field))
     @overload
     def dataclass(
         _cls: Type[_T],
@@ -130,7 +131,7 @@ def dataclass(
 
 else:
 
-    @dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+    @dataclass_transform(field_specifiers=(dataclasses.field, Field))
     @overload
     def dataclass(
         *,
@@ -146,7 +147,7 @@ def dataclass(
     ) -> Callable[[Type[_T]], 'DataclassClassOrWrapper']:
         ...
 
-    @dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+    @dataclass_transform(field_specifiers=(dataclasses.field, Field))
     @overload
     def dataclass(
         _cls: Type[_T],
@@ -164,7 +165,7 @@ def dataclass(
         ...
 
 
-@dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+@dataclass_transform(field_specifiers=(dataclasses.field, Field))
 def dataclass(
     _cls: Optional[Type[_T]] = None,
     *,
@@ -188,8 +189,6 @@ def dataclass(
     the_config = get_config(config)
 
     def wrap(cls: Type[Any]) -> 'DataclassClassOrWrapper':
-        import dataclasses
-
         should_use_proxy = (
             use_proxy
             if use_proxy is not None
@@ -328,7 +327,6 @@ def new_init(self: 'Dataclass', *args: Any, **kwargs: Any) -> None:
             if hasattr(self, '__post_init_post_parse__'):
                 # We need to find again the initvars. To do that we use `__dataclass_fields__` instead of
                 # public method `dataclasses.fields`
-                import dataclasses
 
                 # get all initvars and their default values
                 initvars_and_values: Dict[str, Any] = {}
@@ -377,8 +375,6 @@ def create_pydantic_model_from_dataclass(
     config: Type[Any] = BaseConfig,
     dc_cls_doc: Optional[str] = None,
 ) -> Type['BaseModel']:
-    import dataclasses
-
     field_definitions: Dict[str, Any] = {}
     for field in dataclasses.fields(dc_cls):
         default: Any = Undefined
@@ -466,8 +462,6 @@ class B(A):
     In this case, when we first check `B`, we make an extra check and look at the annotations ('y'),
     which won't be a superset of all the dataclass fields (only the stdlib fields i.e. 'x')
     """
-    import dataclasses
-
     return (
         dataclasses.is_dataclass(_cls)
         and not hasattr(_cls, '__pydantic_model__')

pydantic/main.py

@@ -33,7 +33,6 @@
 from .fields import (
     MAPPING_LIKE_SHAPES,
     Field,
-    FieldInfo,
     ModelField,
     ModelPrivateAttr,
     PrivateAttr,
@@ -118,7 +117,7 @@ def hash_function(self_: Any) -> int:
 _is_base_model_class_defined = False
 
 
-@dataclass_transform(kw_only_default=True, field_specifiers=(Field, FieldInfo))
+@dataclass_transform(kw_only_default=True, field_specifiers=(Field,))
 class ModelMetaclass(ABCMeta):
     @no_type_check  # noqa C901
     def __new__(mcs, name, bases, namespace, **kwargs):  # noqa C901

pydantic/mypy.py

@@ -76,6 +76,7 @@
 METADATA_KEY = 'pydantic-mypy-metadata'
 BASEMODEL_FULLNAME = 'pydantic.main.BaseModel'
 BASESETTINGS_FULLNAME = 'pydantic.env_settings.BaseSettings'
+MODEL_METACLASS_FULLNAME = 'pydantic.main.ModelMetaclass'
 FIELD_FULLNAME = 'pydantic.fields.Field'
 DATACLASS_FULLNAME = 'pydantic.dataclasses.dataclass'
 
@@ -87,6 +88,9 @@ def parse_mypy_version(version: str) -> Tuple[int, ...]:
 MYPY_VERSION_TUPLE = parse_mypy_version(mypy_version)
 BUILTINS_NAME = 'builtins' if MYPY_VERSION_TUPLE >= (0, 930) else '__builtins__'
 
+# Increment version if plugin changes and mypy caches should be invalidated
+PLUGIN_VERSION = 1
+
 
 def plugin(version: str) -> 'TypingType[Plugin]':
     """
@@ -102,6 +106,7 @@ class PydanticPlugin(Plugin):
     def __init__(self, options: Options) -> None:
         self.plugin_config = PydanticPluginConfig(options)
         self._plugin_data = self.plugin_config.to_data()
+        self._plugin_data['version'] = PLUGIN_VERSION
         super().__init__(options)
 
     def get_base_class_hook(self, fullname: str) -> 'Optional[Callable[[ClassDefContext], None]]':
@@ -112,6 +117,11 @@ def get_base_class_hook(self, fullname: str) -> 'Optional[Callable[[ClassDefCont
                 return self._pydantic_model_class_maker_callback
         return None
 
+    def get_metaclass_hook(self, fullname: str) -> Optional[Callable[[ClassDefContext], None]]:
+        if fullname == MODEL_METACLASS_FULLNAME:
+            return self._pydantic_model_metaclass_marker_callback
+        return None
+
     def get_function_hook(self, fullname: str) -> 'Optional[Callable[[FunctionContext], Type]]':
         sym = self.lookup_fully_qualified(fullname)
         if sym and sym.fullname == FIELD_FULLNAME:
@@ -139,6 +149,19 @@ def _pydantic_model_class_maker_callback(self, ctx: ClassDefContext) -> None:
         transformer = PydanticModelTransformer(ctx, self.plugin_config)
         transformer.transform()
 
+    def _pydantic_model_metaclass_marker_callback(self, ctx: ClassDefContext) -> None:
+        """Reset dataclass_transform_spec attribute of ModelMetaclass.
+
+        Let the plugin handle it. This behavior can be disabled
+        if 'debug_dataclass_transform' is set to True', for testing purposes.
+        """
+        if self.plugin_config.debug_dataclass_transform:
+            return
+        info_metaclass = ctx.cls.info.declared_metaclass
+        assert info_metaclass, "callback not passed from 'get_metaclass_hook'"
+        if getattr(info_metaclass.type, 'dataclass_transform_spec', None):
+            info_metaclass.type.dataclass_transform_spec = None  # type: ignore[attr-defined]
+
     def _pydantic_field_callback(self, ctx: FunctionContext) -> 'Type':
         """
         Extract the type of the `default` argument from the Field function, and use it as the return type.
@@ -194,11 +217,18 @@ def _pydantic_field_callback(self, ctx: FunctionContext) -> 'Type':
 
 
 class PydanticPluginConfig:
-    __slots__ = ('init_forbid_extra', 'init_typed', 'warn_required_dynamic_aliases', 'warn_untyped_fields')
+    __slots__ = (
+        'init_forbid_extra',
+        'init_typed',
+        'warn_required_dynamic_aliases',
+        'warn_untyped_fields',
+        'debug_dataclass_transform',
+    )
     init_forbid_extra: bool
     init_typed: bool
     warn_required_dynamic_aliases: bool
     warn_untyped_fields: bool
+    debug_dataclass_transform: bool  # undocumented
 
     def __init__(self, options: Options) -> None:
         if options.config_file is None:  # pragma: no cover