chore: ignore ANN204 to allow __init__ without return type

Replaces mypy-init-return (which only exempts __init__ when args are
typed) with a blanket ANN204 ignore. Special methods have well-known
return types and pyright infers them correctly.

Author: maxisbey

README.v2.md

@@ -532,7 +532,7 @@ def get_user(user_id: str) -> UserProfile:
 
 # Classes WITHOUT type hints cannot be used for structured output
 class UntypedConfig:
-    def __init__(self, setting1, setting2):  # type: ignore[reportMissingParameterType]  # noqa: ANN001, ANN204
+    def __init__(self, setting1, setting2):  # type: ignore[reportMissingParameterType]  # noqa: ANN001
         self.setting1 = setting1
         self.setting2 = setting2
 
@@ -2327,7 +2327,7 @@ from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata, OAu
 class InMemoryTokenStorage(TokenStorage):
     """Demo In-memory token storage implementation."""
 
-    def __init__(self) -> None:
+    def __init__(self):
         self.tokens: OAuthToken | None = None
         self.client_info: OAuthClientInformationFull | None = None
 

examples/snippets/clients/oauth_client.py

@@ -21,7 +21,7 @@
 class InMemoryTokenStorage(TokenStorage):
     """Demo In-memory token storage implementation."""
 
-    def __init__(self) -> None:
+    def __init__(self):
         self.tokens: OAuthToken | None = None
         self.client_info: OAuthClientInformationFull | None = None
 

examples/snippets/servers/structured_output.py

@@ -71,7 +71,7 @@ def get_user(user_id: str) -> UserProfile:
 
 # Classes WITHOUT type hints cannot be used for structured output
 class UntypedConfig:
-    def __init__(self, setting1, setting2):  # type: ignore[reportMissingParameterType]  # noqa: ANN001, ANN204
+    def __init__(self, setting1, setting2):  # type: ignore[reportMissingParameterType]  # noqa: ANN001
         self.setting1 = setting1
         self.setting2 = setting2
 

pyproject.toml

@@ -143,13 +143,13 @@ select = [
     "TID251", # https://docs.astral.sh/ruff/rules/banned-api/
 ]
 ignore = [
+    "ANN204",  # special methods (__init__, __enter__, etc.) have well-known return types
     "ANN401",  # `Any` is sometimes the right type; pyright strict handles real misuse
     "PERF203",
 ]
 
 [tool.ruff.lint.flake8-annotations]
 allow-star-arg-any = true
-mypy-init-return = true
 
 [tool.ruff.lint.flake8-tidy-imports.banned-api]
 "pydantic.RootModel".msg = "Use `pydantic.TypeAdapter` instead."