Don't apply dataclass transform twice with plugin + mypy 1.1.1 (#5162)

* Don't apply dataclass transform twice with plugin + mypy 1.1.1

* Use single quotes

* Add test and fix tuple annotation

* Improvements and test fix

---------

Co-authored-by: David Montague <[email protected]>

Author: cdce8p

changes/5162-cdce8p.md

@@ -0,0 +1 @@
+Fix `InitVar` usage with pydantic dataclasses, mypy version `1.1.1` and the custom mypy plugin

pydantic/mypy.py

@@ -82,14 +82,14 @@
 
 
 def parse_mypy_version(version: str) -> Tuple[int, ...]:
-    return tuple(int(part) for part in version.split('+', 1)[0].split('.'))
+    return tuple(map(int, version.partition('+')[0].split('.')))
 
 
 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
+__version__ = 2
 
 
 def plugin(version: str) -> 'TypingType[Plugin]':
@@ -106,7 +106,6 @@ 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]]':
@@ -134,7 +133,11 @@ def get_method_hook(self, fullname: str) -> Optional[Callable[[MethodContext], T
         return None
 
     def get_class_decorator_hook(self, fullname: str) -> Optional[Callable[[ClassDefContext], None]]:
-        if fullname == DATACLASS_FULLNAME:
+        """Mark pydantic.dataclasses as dataclass.
+
+        Mypy version 1.1.1 added support for `@dataclass_transform` decorator.
+        """
+        if fullname == DATACLASS_FULLNAME and MYPY_VERSION_TUPLE < (1, 1):
             return dataclasses.dataclass_class_maker_callback  # type: ignore[return-value]
         return None
 

tests/mypy/modules/plugin_success.py

@@ -224,3 +224,16 @@ class FieldDefaultTestingModel(BaseModel):
     g: List[int] = Field(default_factory=_default_factory_list)
     h: str = Field(default_factory=_default_factory_str)
     i: str = Field(default_factory=lambda: 'test')
+
+
+# Include the import down here to reduce the effect on line numbers
+from dataclasses import InitVar  # noqa E402
+
+
+@dataclass
+class MyDataClass:
+    foo: InitVar[str]
+    bar: str
+
+
+MyDataClass(foo='foo', bar='bar')

tests/mypy/outputs/plugin_success.txt

@@ -1,3 +1,5 @@
 122: error: Unexpected keyword argument "name" for "AddProject"  [call-arg]
 122: error: Unexpected keyword argument "slug" for "AddProject"  [call-arg]
 122: error: Unexpected keyword argument "description" for "AddProject"  [call-arg]
+239: error: Unexpected keyword argument "foo" for "MyDataClass"  [call-arg]
+239: error: Unexpected keyword argument "bar" for "MyDataClass"  [call-arg]