Remove unused `# type: ignore`s (#12531)

Over time we've begun to use newer versions of mypy, typeshed, stub
packages---and of course we've improved our own annotations. This makes
some type ignore comments no longer necessary. I have removed them.

There was one exception: a module that imports `select.epoll`. The
ignore is redundant on Linux, but I've kept it ignored for those of us
who work on the source tree using not-Linux. (#11771)

I'm more interested in the config line which enforces this. I want
unused ignores to be reported, because I think it's useful feedback when
annotating to know when you've fixed a problem you had to previously
ignore.

* Installing extras before typechecking

Lacking an easy way to install all extras generically, let's bite the bullet and
make install the hand-maintained `all` extra before typechecking.

Now that https://github.com/matrix-org/backend-meta/pull/6 is merged to
the release/v1 branch.

12 files changed, 27 insertions, 27 deletions

diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index 37321f9133..d28b87a3f4 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -48,7 +48,6 @@ from twisted.logger import LoggingFile, LogLevel
 from twisted.protocols.tls import TLSMemoryBIOFactory
 from twisted.python.threadpool import ThreadPool
 
-import synapse
 from synapse.api.constants import MAX_PDU_SIZE
 from synapse.app import check_bind_error
 from synapse.app.phone_stats_home import start_phone_stats_home
@@ -60,6 +59,7 @@ from synapse.events.spamcheck import load_legacy_spam_checkers
 from synapse.events.third_party_rules import load_legacy_third_party_event_rules
 from synapse.handlers.auth import load_legacy_password_auth_providers
 from synapse.logging.context import PreserveLoggingContext
+from synapse.logging.opentracing import init_tracer
 from synapse.metrics import install_gc_manager, register_threadpool
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.metrics.jemalloc import setup_jemalloc_stats
@@ -431,7 +431,7 @@ async def start(hs: "HomeServer") -> None:
     refresh_certificate(hs)
 
     # Start the tracer
-    synapse.logging.opentracing.init_tracer(hs)  # type: ignore[attr-defined] # noqa
+    init_tracer(hs)  # noqa
 
     # Instantiate the modules so they can register their web resources to the module API
     # before we start the listeners.
diff --git a/synapse/config/server.py b/synapse/config/server.py
index d771045b52..b6cd326416 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -186,7 +186,7 @@ KNOWN_RESOURCES = {
 class HttpResourceConfig:
     names: List[str] = attr.ib(
         factory=list,
-        validator=attr.validators.deep_iterable(attr.validators.in_(KNOWN_RESOURCES)),  # type: ignore
+        validator=attr.validators.deep_iterable(attr.validators.in_(KNOWN_RESOURCES)),
     )
     compress: bool = attr.ib(
         default=False,
@@ -231,9 +231,7 @@ class ManholeConfig:
 class LimitRemoteRoomsConfig:
     enabled: bool = attr.ib(validator=attr.validators.instance_of(bool), default=False)
     complexity: Union[float, int] = attr.ib(
-        validator=attr.validators.instance_of(
-            (float, int)  # type: ignore[arg-type] # noqa
-        ),
+        validator=attr.validators.instance_of((float, int)),  # noqa
         default=1.0,
     )
     complexity_error: str = attr.ib(
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index beab1227b8..884b5d60b4 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -268,8 +268,8 @@ class FederationServer(FederationBase):
             transaction_id=transaction_id,
             destination=destination,
             origin=origin,
-            origin_server_ts=transaction_data.get("origin_server_ts"),  # type: ignore
-            pdus=transaction_data.get("pdus"),  # type: ignore
+            origin_server_ts=transaction_data.get("origin_server_ts"),  # type: ignore[arg-type]
+            pdus=transaction_data.get("pdus"),
             edus=transaction_data.get("edus"),
         )
 
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 1421050b9a..9ce06dfa28 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -229,21 +229,21 @@ class TransportLayerClient:
         """
         logger.debug(
             "send_data dest=%s, txid=%s",
-            transaction.destination,  # type: ignore
-            transaction.transaction_id,  # type: ignore
+            transaction.destination,
+            transaction.transaction_id,
         )
 
-        if transaction.destination == self.server_name:  # type: ignore
+        if transaction.destination == self.server_name:
             raise RuntimeError("Transport layer cannot send to itself!")
 
         # FIXME: This is only used by the tests. The actual json sent is
         # generated by the json_data_callback.
         json_data = transaction.get_dict()
 
-        path = _create_v1_path("/send/%s", transaction.transaction_id)  # type: ignore
+        path = _create_v1_path("/send/%s", transaction.transaction_id)
 
         return await self.client.put_json(
-            transaction.destination,  # type: ignore
+            transaction.destination,
             path=path,
             data=json_data,
             json_data_callback=json_data_callback,
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 86991d26ce..22678d486d 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -481,7 +481,7 @@ class AuthHandler:
             sid = authdict["session"]
 
         # Convert the URI and method to strings.
-        uri = request.uri.decode("utf-8")  # type: ignore
+        uri = request.uri.decode("utf-8")
         method = request.method.decode("utf-8")
 
         # If there's no session ID, create a new session.
diff --git a/synapse/handlers/oidc.py b/synapse/handlers/oidc.py
index 724b9cfcb4..f6ffb7d18d 100644
--- a/synapse/handlers/oidc.py
+++ b/synapse/handlers/oidc.py
@@ -966,7 +966,7 @@ class OidcProvider:
                         "Mapping provider does not support de-duplicating Matrix IDs"
                     )
 
-                attributes = await self._user_mapping_provider.map_user_attributes(  # type: ignore
+                attributes = await self._user_mapping_provider.map_user_attributes(
                     userinfo, token
                 )
 
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 102dd4b57d..5619f8f50e 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -357,7 +357,7 @@ class SearchHandler:
             itertools.chain(
                 # The events_before and events_after for each context.
                 itertools.chain.from_iterable(
-                    itertools.chain(context["events_before"], context["events_after"])  # type: ignore[arg-type]
+                    itertools.chain(context["events_before"], context["events_after"])
                     for context in contexts.values()
                 ),
                 # The returned events.
@@ -373,10 +373,10 @@ class SearchHandler:
 
         for context in contexts.values():
             context["events_before"] = self._event_serializer.serialize_events(
-                context["events_before"], time_now, bundle_aggregations=aggregations  # type: ignore[arg-type]
+                context["events_before"], time_now, bundle_aggregations=aggregations
             )
             context["events_after"] = self._event_serializer.serialize_events(
-                context["events_after"], time_now, bundle_aggregations=aggregations  # type: ignore[arg-type]
+                context["events_after"], time_now, bundle_aggregations=aggregations
             )
 
         results = [
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 31ca841889..b8a7a0f5df 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -295,7 +295,7 @@ class _AsyncResource(resource.Resource, metaclass=abc.ABCMeta):
             if isawaitable(raw_callback_return):
                 callback_return = await raw_callback_return
             else:
-                callback_return = raw_callback_return  # type: ignore
+                callback_return = raw_callback_return
 
             return callback_return
 
@@ -469,7 +469,7 @@ class JsonResource(DirectServeJsonResource):
         if isinstance(raw_callback_return, (defer.Deferred, types.CoroutineType)):
             callback_return = await raw_callback_return
         else:
-            callback_return = raw_callback_return  # type: ignore
+            callback_return = raw_callback_return
 
         return callback_return
 
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 8f9e629274..7e6e23db73 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -109,6 +109,7 @@ from synapse.storage.state import StateFilter
 from synapse.types import (
     DomainSpecificString,
     JsonDict,
+    JsonMapping,
     Requester,
     StateMap,
     UserID,
@@ -151,6 +152,7 @@ __all__ = [
     "PRESENCE_ALL_USERS",
     "LoginResponse",
     "JsonDict",
+    "JsonMapping",
     "EventBase",
     "StateMap",
     "ProfileInfo",
@@ -1419,7 +1421,7 @@ class AccountDataManager:
                 f"{user_id} is not local to this homeserver; can't access account data for remote users."
             )
 
-    async def get_global(self, user_id: str, data_type: str) -> Optional[JsonDict]:
+    async def get_global(self, user_id: str, data_type: str) -> Optional[JsonMapping]:
         """
         Gets some global account data, of a specified type, for the specified user.
 
diff --git a/synapse/storage/databases/main/monthly_active_users.py b/synapse/storage/databases/main/monthly_active_users.py
index 4f1c22c71b..5beb8f1d4b 100644
--- a/synapse/storage/databases/main/monthly_active_users.py
+++ b/synapse/storage/databases/main/monthly_active_users.py
@@ -232,10 +232,10 @@ class MonthlyActiveUsersWorkerStore(RegistrationWorkerStore):
             # is racy.
             # Have resolved to invalidate the whole cache for now and do
             # something about it if and when the perf becomes significant
-            self._invalidate_all_cache_and_stream(  # type: ignore[attr-defined]
+            self._invalidate_all_cache_and_stream(
                 txn, self.user_last_seen_monthly_active
             )
-            self._invalidate_cache_and_stream(txn, self.get_monthly_active_count, ())  # type: ignore[attr-defined]
+            self._invalidate_cache_and_stream(txn, self.get_monthly_active_count, ())
 
         reserved_users = await self.get_registered_reserved_users()
         await self.db_pool.runInteraction(
@@ -363,7 +363,7 @@ class MonthlyActiveUsersWorkerStore(RegistrationWorkerStore):
 
         if self._limit_usage_by_mau or self._mau_stats_only:
             # Trial users and guests should not be included as part of MAU group
-            is_guest = await self.is_guest(user_id)  # type: ignore[attr-defined]
+            is_guest = await self.is_guest(user_id)
             if is_guest:
                 return
             is_trial = await self.is_trial_user(user_id)
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index e3153d1a4a..546d6bae6e 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -501,11 +501,11 @@ def _upgrade_existing_database(
 
                 if hasattr(module, "run_create"):
                     logger.info("Running %s:run_create", relative_path)
-                    module.run_create(cur, database_engine)  # type: ignore
+                    module.run_create(cur, database_engine)
 
                 if not is_empty and hasattr(module, "run_upgrade"):
                     logger.info("Running %s:run_upgrade", relative_path)
-                    module.run_upgrade(cur, database_engine, config=config)  # type: ignore
+                    module.run_upgrade(cur, database_engine, config=config)
             elif ext == ".pyc" or file_name == "__pycache__":
                 # Sometimes .pyc files turn up anyway even though we've
                 # disabled their generation; e.g. from distribution package
diff --git a/synapse/util/caches/ttlcache.py b/synapse/util/caches/ttlcache.py
index 0b9ac26b69..f6b3ee31e4 100644
--- a/synapse/util/caches/ttlcache.py
+++ b/synapse/util/caches/ttlcache.py
@@ -107,7 +107,7 @@ class TTLCache(Generic[KT, VT]):
         self._metrics.inc_hits()
         return e.value, e.expiry_time, e.ttl
 
-    def pop(self, key: KT, default: T = SENTINEL) -> Union[VT, T]:  # type: ignore
+    def pop(self, key: KT, default: T = SENTINEL) -> Union[VT, T]:
         """Remove a value from the cache
 
         If key is in the cache, remove it and return its value, else return default.