Use mypy 1.0

changelog.d/15052.misc

@@ -0,0 +1 @@
+Improve type hints.

synapse/handlers/auth.py

@@ -199,7 +199,10 @@ def __init__(self, hs: "HomeServer"):
         self.clock = hs.get_clock()
         self.checkers: Dict[str, UserInteractiveAuthChecker] = {}
         for auth_checker_class in INTERACTIVE_AUTH_CHECKERS:
-            inst = auth_checker_class(hs)
+            # mypy sees that the expression `auth_checker_class(hs)` is an instance of
+            # `UserInteractiveAuthChecker`, but cannot see that it is an instance of
+            # a non-abstract subclass.
+            inst = auth_checker_class(hs)  # type: ignore[abstract]
             if inst.is_enabled():
                 self.checkers[inst.AUTH_TYPE] = inst  # type: ignore
 

synapse/handlers/ui_auth/checkers.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import logging
+from abc import ABC, abstractmethod
 from typing import TYPE_CHECKING, Any
 
 from twisted.web.client import PartialDownloadError
@@ -27,19 +28,22 @@
 logger = logging.getLogger(__name__)
 
 
-class UserInteractiveAuthChecker:
+class UserInteractiveAuthChecker(ABC):
     """Abstract base class for an interactive auth checker"""
 
-    def __init__(self, hs: "HomeServer"):
+    def __init__(self, hs: "HomeServer"):  # noqa: B027
         pass
 
+    @abstractmethod
     def is_enabled(self) -> bool:
         """Check if the configuration of the homeserver allows this checker to work
 
         Returns:
             True if this login type is enabled.
         """
+        raise NotImplementedError()
 
+    @abstractmethod
     async def check_auth(self, authdict: dict, clientip: str) -> Any:
         """Given the authentication dict from the client, attempt to check this step
 

synapse/http/matrixfederationclient.py

@@ -1267,7 +1267,7 @@ async def get_file(
 def _flatten_response_never_received(e: BaseException) -> str:
     if hasattr(e, "reasons"):
         reasons = ", ".join(
-            _flatten_response_never_received(f.value) for f in e.reasons  # type: ignore[attr-defined]
+            _flatten_response_never_received(f.value) for f in e.reasons
         )
 
         return "%s:[%s]" % (type(e).__name__, reasons)

synapse/logging/opentracing.py

@@ -188,7 +188,7 @@ def set_fates(clotho, lachesis, atropos, father="Zues", mother="Themis"):
 )
 
 import attr
-from typing_extensions import ParamSpec
+from typing_extensions import Concatenate, ParamSpec
 
 from twisted.internet import defer
 from twisted.web.http import Request
@@ -445,7 +445,7 @@ def init_tracer(hs: "HomeServer") -> None:
         opentracing = None  # type: ignore[assignment]
         return
 
-    if not opentracing or not JaegerConfig:
+    if opentracing is None or JaegerConfig is None:
         raise ConfigError(
             "The server has been configured to use opentracing but opentracing is not "
             "installed."
@@ -864,7 +864,7 @@ def extract_text_map(carrier: Dict[str, str]) -> Optional["opentracing.SpanConte
 
 def _custom_sync_async_decorator(
     func: Callable[P, R],
-    wrapping_logic: Callable[[Callable[P, R], Any, Any], ContextManager[None]],
+    wrapping_logic: Callable[Concatenate[Callable[P, R], P], ContextManager[None]],
 ) -> Callable[P, R]:
     """
     Decorates a function that is sync or async (coroutines), or that returns a Twisted
@@ -894,10 +894,14 @@ def _wrapping_logic(func: Callable[P, R], *args: P.args, **kwargs: P.kwargs) ->
     """
 
     if inspect.iscoroutinefunction(func):
-
+        # In this branch, R = Awaitable[RInner], for some other type RInner
         @wraps(func)
-        async def _wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+        async def _wrapper(
+            *args: P.args, **kwargs: P.kwargs
+        ) -> Any:  # Return type is RInner
             with wrapping_logic(func, *args, **kwargs):
+                # type-ignore: func() returns R, but mypy doesn't know that R is
+                # Awaitable here.
                 return await func(*args, **kwargs)  # type: ignore[misc]
 
     else:
@@ -964,7 +968,11 @@ def _decorator(func: Callable[P, R]) -> Callable[P, R]:
         if not opentracing:
             return func
 
-        return _custom_sync_async_decorator(func, _wrapping_logic)
+        # type-ignore: mypy seems to be confused by the ParamSpecs here.
+        # I think the problem is https://github.com/python/mypy/issues/12909
+        return _custom_sync_async_decorator(
+            func, _wrapping_logic  # type: ignore[arg-type]
+        )
 
     return _decorator
 
@@ -1010,7 +1018,9 @@ def _wrapping_logic(
         set_tag(SynapseTags.FUNC_KWARGS, str(kwargs))
         yield
 
-    return _custom_sync_async_decorator(func, _wrapping_logic)
+    # type-ignore: mypy seems to be confused by the ParamSpecs here.
+    # I think the problem is https://github.com/python/mypy/issues/12909
+    return _custom_sync_async_decorator(func, _wrapping_logic)  # type: ignore[arg-type]
 
 
 @contextlib.contextmanager

synapse/rest/media/v1/_base.py

@@ -16,6 +16,7 @@
 import logging
 import os
 import urllib
+from abc import ABC, abstractmethod
 from types import TracebackType
 from typing import Awaitable, Dict, Generator, List, Optional, Tuple, Type
 
@@ -284,13 +285,14 @@ async def respond_with_responder(
     finish_request(request)
 
 
-class Responder:
+class Responder(ABC):
     """Represents a response that can be streamed to the requester.
 
     Responder is a context manager which *must* be used, so that any resources
     held can be cleaned up.
     """
 
+    @abstractmethod
     def write_to_consumer(self, consumer: IConsumer) -> Awaitable:
         """Stream response into consumer
 
@@ -300,11 +302,12 @@ def write_to_consumer(self, consumer: IConsumer) -> Awaitable:
         Returns:
             Resolves once the response has finished being written
         """
+        raise NotImplementedError()
 
-    def __enter__(self) -> None:
+    def __enter__(self) -> None:  # noqa: B027
         pass
 
-    def __exit__(
+    def __exit__(  # noqa: B027
         self,
         exc_type: Optional[Type[BaseException]],
         exc_val: Optional[BaseException],

synapse/storage/engines/__init__.py

@@ -25,7 +25,7 @@
 except ImportError:
 
     class PostgresEngine(BaseDatabaseEngine):  # type: ignore[no-redef]
-        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:  # type: ignore[misc]
+        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
             raise RuntimeError(
                 f"Cannot create {cls.__name__} -- psycopg2 module is not installed"
             )
@@ -36,7 +36,7 @@ def __new__(cls, *args: object, **kwargs: object) -> NoReturn:  # type: ignore[m
 except ImportError:
 
     class Sqlite3Engine(BaseDatabaseEngine):  # type: ignore[no-redef]
-        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:  # type: ignore[misc]
+        def __new__(cls, *args: object, **kwargs: object) -> NoReturn:
             raise RuntimeError(
                 f"Cannot create {cls.__name__} -- sqlite3 module is not installed"
             )