Optimize default plugin

Author: JukkaL

mypy/plugins/default.py

@@ -15,6 +15,7 @@
     MethodSigContext,
     Plugin,
 )
+from mypy.plugins import singledispatch_const
 from mypy.plugins.common import try_getting_str_literals
 from mypy.subtypes import is_subtype
 from mypy.typeops import is_literal_type_like, make_simplified_union
@@ -36,6 +37,16 @@
     get_proper_types,
 )
 
+TD_SETDEFAULT_NAMES: Final = {n + ".setdefault" for n in TPDICT_FB_NAMES}
+TD_POP_NAMES: Final = {n + ".pop" for n in TPDICT_FB_NAMES}
+
+TD_UPDATE_METHOD_NAMES: Final = (
+    {n + ".update" for n in TPDICT_FB_NAMES}
+    | {n + ".__or__" for n in TPDICT_FB_NAMES}
+    | {n + ".__ror__" for n in TPDICT_FB_NAMES}
+    | {n + ".__ior__" for n in TPDICT_FB_NAMES}
+)
+
 
 class DefaultPlugin(Plugin):
     """Type checker plugin that is enabled by default."""
@@ -72,34 +83,25 @@ def get_function_signature_hook(
     def get_method_signature_hook(
         self, fullname: str
     ) -> Callable[[MethodSigContext], FunctionLike] | None:
-        from mypy.plugins import ctypes, singledispatch
-
         if fullname == "typing.Mapping.get":
             return typed_dict_get_signature_callback
-        elif fullname in {n + ".setdefault" for n in TPDICT_FB_NAMES}:
+        elif fullname in TD_SETDEFAULT_NAMES:
             return typed_dict_setdefault_signature_callback
-        elif fullname in {n + ".pop" for n in TPDICT_FB_NAMES}:
+        elif fullname in TD_POP_NAMES:
             return typed_dict_pop_signature_callback
         elif fullname == "_ctypes.Array.__setitem__":
-            return ctypes.array_setitem_callback
-        elif fullname == singledispatch.SINGLEDISPATCH_CALLABLE_CALL_METHOD:
-            return singledispatch.call_singledispatch_function_callback
+            from mypy.plugins import ctypes
 
-        typed_dict_updates = set()
-        for n in TPDICT_FB_NAMES:
-            typed_dict_updates.add(n + ".update")
-            typed_dict_updates.add(n + ".__or__")
-            typed_dict_updates.add(n + ".__ror__")
-            typed_dict_updates.add(n + ".__ior__")
+            return ctypes.array_setitem_callback
+        elif fullname == singledispatch_const.SINGLEDISPATCH_CALLABLE_CALL_METHOD:
+            from mypy.plugins import singledispatch
 
-        if fullname in typed_dict_updates:
+            return singledispatch.call_singledispatch_function_callback
+        elif fullname in TD_UPDATE_METHOD_NAMES:
             return typed_dict_update_signature_callback
-
         return None
 
     def get_method_hook(self, fullname: str) -> Callable[[MethodContext], Type] | None:
-        from mypy.plugins import ctypes, singledispatch
-
         if fullname == "typing.Mapping.get":
             return typed_dict_get_callback
         elif fullname == "builtins.int.__pow__":
@@ -117,12 +119,20 @@ def get_method_hook(self, fullname: str) -> Callable[[MethodContext], Type] | No
         elif fullname in {n + ".__delitem__" for n in TPDICT_FB_NAMES}:
             return typed_dict_delitem_callback
         elif fullname == "_ctypes.Array.__getitem__":
+            from mypy.plugins import ctypes
+
             return ctypes.array_getitem_callback
         elif fullname == "_ctypes.Array.__iter__":
+            from mypy.plugins import ctypes
+
             return ctypes.array_iter_callback
-        elif fullname == singledispatch.SINGLEDISPATCH_REGISTER_METHOD:
+        elif fullname == singledispatch_const.SINGLEDISPATCH_REGISTER_METHOD:
+            from mypy.plugins import singledispatch
+
             return singledispatch.singledispatch_register_callback
-        elif fullname == singledispatch.REGISTER_CALLABLE_CALL_METHOD:
+        elif fullname == singledispatch_const.REGISTER_CALLABLE_CALL_METHOD:
+            from mypy.plugins import singledispatch
+
             return singledispatch.call_singledispatch_function_after_register_argument
         elif fullname == "functools.partial.__call__":
             import mypy.plugins.functools

mypy/plugins/singledispatch.py

@@ -1,14 +1,15 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-from typing import Final, NamedTuple, TypeVar, Union
+from typing import NamedTuple, TypeVar, Union
 from typing_extensions import TypeAlias as _TypeAlias
 
 from mypy.messages import format_type
 from mypy.nodes import ARG_POS, Argument, Block, ClassDef, Context, SymbolTable, TypeInfo, Var
 from mypy.options import Options
 from mypy.plugin import CheckerPluginInterface, FunctionContext, MethodContext, MethodSigContext
 from mypy.plugins.common import add_method_to_class
+from mypy.plugins.singledispatch_const import REGISTER_RETURN_CLASS
 from mypy.subtypes import is_subtype
 from mypy.types import (
     AnyType,
@@ -33,13 +34,6 @@ class RegisterCallableInfo(NamedTuple):
     singledispatch_obj: Instance
 
 
-SINGLEDISPATCH_TYPE: Final = "functools._SingleDispatchCallable"
-
-SINGLEDISPATCH_REGISTER_METHOD: Final = f"{SINGLEDISPATCH_TYPE}.register"
-
-SINGLEDISPATCH_CALLABLE_CALL_METHOD: Final = f"{SINGLEDISPATCH_TYPE}.__call__"
-
-
 def get_singledispatch_info(typ: Instance) -> SingledispatchTypeVars | None:
     if len(typ.args) == 2:
         return SingledispatchTypeVars(*typ.args)  # type: ignore[arg-type]
@@ -56,11 +50,6 @@ def get_first_arg(args: list[list[T]]) -> T | None:
     return None
 
 
-REGISTER_RETURN_CLASS: Final = "_SingleDispatchRegisterCallable"
-
-REGISTER_CALLABLE_CALL_METHOD: Final = f"functools.{REGISTER_RETURN_CLASS}.__call__"
-
-
 def make_fake_register_class_instance(
     api: CheckerPluginInterface, type_args: Sequence[Type]
 ) -> Instance:

mypy/plugins/singledispatch_const.py

@@ -0,0 +1,13 @@
+"""Constant definitions for singledispatch plugin moved here to help with import cycle."""
+
+from typing import Final
+
+SINGLEDISPATCH_TYPE: Final = "functools._SingleDispatchCallable"
+
+SINGLEDISPATCH_REGISTER_METHOD: Final = f"{SINGLEDISPATCH_TYPE}.register"
+
+SINGLEDISPATCH_CALLABLE_CALL_METHOD: Final = f"{SINGLEDISPATCH_TYPE}.__call__"
+
+REGISTER_RETURN_CLASS: Final = "_SingleDispatchRegisterCallable"
+
+REGISTER_CALLABLE_CALL_METHOD: Final = f"functools.{REGISTER_RETURN_CLASS}.__call__"