Improve message base class

proto-stubs/message.pyi

@@ -1,49 +1,63 @@
-from typing import Any, List, Type
+from collections.abc import Mapping
+from typing import Any, TypeVar, overload
 
 from google.protobuf import descriptor_pb2, message
 
 from proto.fields import Field
 from proto.marshal import Marshal
 
+_M = TypeVar("_M")
+
 class MessageMeta(type):
     def __new__(mcls, name, bases, attrs): ...
     @classmethod
     def __prepare__(mcls, name, bases, **kwargs): ...
     @property
     def meta(cls): ...
-    def pb(cls, obj: Any | None = ..., *, coerce: bool = ...): ...
-    def wrap(cls, pb): ...
-    def serialize(cls, instance) -> bytes: ...
-    def deserialize(cls, payload: bytes) -> Message: ...
+    @overload
+    def pb(
+        cls: type[_M], obj: None = ..., *, coerce: bool = ...
+    ) -> type[message.Message]: ...
+    @overload
+    def pb(cls: type[_M], obj: _M, *, coerce: bool = ...) -> message.Message: ...
+    def wrap(cls: type[_M], pb: message.Message) -> _M: ...
+    def serialize(cls: type[_M], instance: _M | Mapping | message.Message) -> bytes: ...
+    def deserialize(cls: type[_M], payload: bytes) -> _M: ...
     def to_json(
-        cls,
-        instance,
+        cls: type[_M],
+        instance: _M,
         *,
         use_integers_for_enums: bool = ...,
         including_default_value_fields: bool = ...,
         preserving_proto_field_name: bool = ...
     ) -> str: ...
-    def from_json(cls, payload, *, ignore_unknown_fields: bool = ...) -> Message: ...
+    def from_json(
+        cls: type[_M], payload: str, *, ignore_unknown_fields: bool = ...
+    ) -> _M: ...
     def to_dict(
-        cls,
-        instance,
+        cls: type[_M],
+        instance: _M,
         *,
         use_integers_for_enums: bool = ...,
         preserving_proto_field_name: bool = ...
-    ) -> Message: ...
-    def copy_from(cls, instance, other) -> None: ...
+    ) -> dict[str, Any]: ...
+    def copy_from(
+        cls: type[_M], instance: _M | Mapping | message.Message, other
+    ) -> None: ...
 
 class Message(metaclass=MessageMeta):
     def __init__(
-        self, mapping: Any | None = ..., *, ignore_unknown_fields: bool = ..., **kwargs
+        self: _M,
+        mapping: _M | Mapping | message.Message | None = ...,
+        *,
+        ignore_unknown_fields: bool = ...,
+        **kwargs
     ) -> None: ...
-    def __bool__(self): ...
-    def __contains__(self, key): ...
-    def __delattr__(self, key) -> None: ...
-    def __eq__(self, other): ...
-    def __getattr__(self, key): ...
-    def __ne__(self, other): ...
-    def __setattr__(self, key, value): ...
+    def __bool__(self) -> bool: ...
+    def __contains__(self, key: str) -> bool: ...
+    def __delattr__(self, key: str) -> None: ...
+    def __eq__(self, other: Any) -> bool: ...
+    def __ne__(self, other: Any) -> bool: ...
 
 class _MessageInfo:
     package: Any
@@ -54,11 +68,11 @@ class _MessageInfo:
     marshal: Any
     def __init__(
         self,
-        fields: List[Field],
+        fields: list[Field],
         package: str,
         full_name: str,
         marshal: Marshal,
         options: descriptor_pb2.MessageOptions,
     ) -> None: ...
     @property
-    def pb(self) -> Type[message.Message]: ...
+    def pb(self) -> type[message.Message]: ...

pyproject.toml

@@ -19,7 +19,7 @@ proto-plus = ">=1.18.0"
 types-protobuf = ">=3.17.4"
 
 [tool.poetry.group.dev.dependencies]
-mypy = "^0.990"
+mypy = {version = "^1.7.0", python = "^3.8"}
 black = "^22.10.0"
 isort = "^5.10.1"