feat: add support of StrictUnion with mypy plugin

pydantic/mypy.py

@@ -34,7 +34,14 @@
     Var,
 )
 from mypy.options import Options
-from mypy.plugin import CheckerPluginInterface, ClassDefContext, MethodContext, Plugin, SemanticAnalyzerPluginInterface
+from mypy.plugin import (
+    AnalyzeTypeContext,
+    CheckerPluginInterface,
+    ClassDefContext,
+    MethodContext,
+    Plugin,
+    SemanticAnalyzerPluginInterface,
+)
 from mypy.plugins import dataclasses
 from mypy.semanal import set_callable_name  # type: ignore
 from mypy.server.trigger import make_wildcard_trigger
@@ -95,11 +102,22 @@ def get_class_decorator_hook(self, fullname: str) -> Optional[Callable[[ClassDef
             return dataclasses.dataclass_class_maker_callback
         return None
 
+    def get_type_analyze_hook(self, fullname: str) -> Optional[Callable[[AnalyzeTypeContext], Type]]:
+        if fullname == 'pydantic.types.StrictUnion':
+            return _convert_strict_union_type
+        return None
+
     def _pydantic_model_class_maker_callback(self, ctx: ClassDefContext) -> None:
         transformer = PydanticModelTransformer(ctx, self.plugin_config)
         transformer.transform()
 
 
+def _convert_strict_union_type(type_context: AnalyzeTypeContext) -> Type:
+    """Convert StrictUnion[...] type to Union[...]"""
+    union_mypy_types: Tuple[Type, ...] = type_context.type.args  # e.g. (int?, bool?, str?)
+    return UnionType(items=union_mypy_types, line=type_context.type.line, column=type_context.type.column)
+
+
 class PydanticPluginConfig:
     __slots__ = ('init_forbid_extra', 'init_typed', 'warn_required_dynamic_aliases', 'warn_untyped_fields')
     init_forbid_extra: bool

tests/mypy/modules/plugin_success.py

@@ -1,6 +1,6 @@
 from typing import ClassVar, Optional, Union
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, StrictUnion
 from pydantic.dataclasses import dataclass
 
 
@@ -133,3 +133,10 @@ class Model(BaseModel):
 
 
 _ = NestedModel.Model
+
+
+class PikaModel(BaseModel):
+    x: StrictUnion[int, bool, str]
+
+
+pika = PikaModel(x=123)

tests/mypy/outputs/plugin_success.txt

@@ -1,3 +1,5 @@
 121: error: Unexpected keyword argument "name" for "AddProject"  [call-arg]
 121: error: Unexpected keyword argument "slug" for "AddProject"  [call-arg]
-121: error: Unexpected keyword argument "description" for "AddProject"  [call-arg]
+121: error: Unexpected keyword argument "description" for "AddProject"  [call-arg]
+139: error: Variable "pydantic.types.StrictUnion" is not valid as a type  [valid-type]
+139: note: See https://mypy.readthedocs.io/en/latest/common_issues.html#variables-vs-type-aliases