Reduce the number of "untyped defs" (#12716)

7 files changed, 76 insertions, 39 deletions

diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index 41f566b648..5ddb58a8a2 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -31,6 +31,7 @@ from typing import (
     List,
     Optional,
     Tuple,
+    Type,
     TypeVar,
     cast,
     overload,
@@ -41,6 +42,7 @@ from prometheus_client import Histogram
 from typing_extensions import Concatenate, Literal, ParamSpec
 
 from twisted.enterprise import adbapi
+from twisted.internet.interfaces import IReactorCore
 
 from synapse.api.errors import StoreError
 from synapse.config.database import DatabaseConnectionConfig
@@ -92,7 +94,9 @@ UNIQUE_INDEX_BACKGROUND_UPDATES = {
 
 
 def make_pool(
-    reactor, db_config: DatabaseConnectionConfig, engine: BaseDatabaseEngine
+    reactor: IReactorCore,
+    db_config: DatabaseConnectionConfig,
+    engine: BaseDatabaseEngine,
 ) -> adbapi.ConnectionPool:
     """Get the connection pool for the database."""
 
@@ -101,7 +105,7 @@ def make_pool(
     db_args = dict(db_config.config.get("args", {}))
     db_args.setdefault("cp_reconnect", True)
 
-    def _on_new_connection(conn):
+    def _on_new_connection(conn: Connection) -> None:
         # Ensure we have a logging context so we can correctly track queries,
         # etc.
         with LoggingContext("db.on_new_connection"):
@@ -157,7 +161,11 @@ class LoggingDatabaseConnection:
     default_txn_name: str
 
     def cursor(
-        self, *, txn_name=None, after_callbacks=None, exception_callbacks=None
+        self,
+        *,
+        txn_name: Optional[str] = None,
+        after_callbacks: Optional[List["_CallbackListEntry"]] = None,
+        exception_callbacks: Optional[List["_CallbackListEntry"]] = None,
     ) -> "LoggingTransaction":
         if not txn_name:
             txn_name = self.default_txn_name
@@ -183,11 +191,16 @@ class LoggingDatabaseConnection:
         self.conn.__enter__()
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback) -> Optional[bool]:
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_value: Optional[BaseException],
+        traceback: Optional[types.TracebackType],
+    ) -> Optional[bool]:
         return self.conn.__exit__(exc_type, exc_value, traceback)
 
     # Proxy through any unknown lookups to the DB conn class.
-    def __getattr__(self, name):
+    def __getattr__(self, name: str) -> Any:
         return getattr(self.conn, name)
 
 
@@ -391,17 +404,22 @@ class LoggingTransaction:
     def __enter__(self) -> "LoggingTransaction":
         return self
 
-    def __exit__(self, exc_type, exc_value, traceback):
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_value: Optional[BaseException],
+        traceback: Optional[types.TracebackType],
+    ) -> None:
         self.close()
 
 
 class PerformanceCounters:
-    def __init__(self):
-        self.current_counters = {}
-        self.previous_counters = {}
+    def __init__(self) -> None:
+        self.current_counters: Dict[str, Tuple[int, float]] = {}
+        self.previous_counters: Dict[str, Tuple[int, float]] = {}
 
     def update(self, key: str, duration_secs: float) -> None:
-        count, cum_time = self.current_counters.get(key, (0, 0))
+        count, cum_time = self.current_counters.get(key, (0, 0.0))
         count += 1
         cum_time += duration_secs
         self.current_counters[key] = (count, cum_time)
@@ -527,7 +545,7 @@ class DatabasePool:
     def start_profiling(self) -> None:
         self._previous_loop_ts = monotonic_time()
 
-        def loop():
+        def loop() -> None:
             curr = self._current_txn_total_time
             prev = self._previous_txn_total_time
             self._previous_txn_total_time = curr
@@ -1186,7 +1204,7 @@ class DatabasePool:
         if lock:
             self.engine.lock_table(txn, table)
 
-        def _getwhere(key):
+        def _getwhere(key: str) -> str:
             # If the value we're passing in is None (aka NULL), we need to use
             # IS, not =, as NULL = NULL equals NULL (False).
             if keyvalues[key] is None:
@@ -2258,7 +2276,7 @@ class DatabasePool:
         term: Optional[str],
         col: str,
         retcols: Collection[str],
-        desc="simple_search_list",
+        desc: str = "simple_search_list",
     ) -> Optional[List[Dict[str, Any]]]:
         """Executes a SELECT query on the named table, which may return zero or
         more rows, returning the result as a list of dicts.
diff --git a/synapse/storage/databases/main/metrics.py b/synapse/storage/databases/main/metrics.py
index 1480a0f048..d03555a585 100644
--- a/synapse/storage/databases/main/metrics.py
+++ b/synapse/storage/databases/main/metrics.py
@@ -23,6 +23,7 @@ from synapse.storage.database import DatabasePool, LoggingDatabaseConnection
 from synapse.storage.databases.main.event_push_actions import (
     EventPushActionsWorkerStore,
 )
+from synapse.storage.types import Cursor
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -71,7 +72,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
         self._last_user_visit_update = self._get_start_of_day()
 
     @wrap_as_background_process("read_forward_extremities")
-    async def _read_forward_extremities(self):
+    async def _read_forward_extremities(self) -> None:
         def fetch(txn):
             txn.execute(
                 """
@@ -95,7 +96,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             (x[0] - 1) * x[1] for x in res if x[1]
         )
 
-    async def count_daily_e2ee_messages(self):
+    async def count_daily_e2ee_messages(self) -> int:
         """
         Returns an estimate of the number of messages sent in the last day.
 
@@ -115,7 +116,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
 
         return await self.db_pool.runInteraction("count_e2ee_messages", _count_messages)
 
-    async def count_daily_sent_e2ee_messages(self):
+    async def count_daily_sent_e2ee_messages(self) -> int:
         def _count_messages(txn):
             # This is good enough as if you have silly characters in your own
             # hostname then that's your own fault.
@@ -136,7 +137,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             "count_daily_sent_e2ee_messages", _count_messages
         )
 
-    async def count_daily_active_e2ee_rooms(self):
+    async def count_daily_active_e2ee_rooms(self) -> int:
         def _count(txn):
             sql = """
                 SELECT COUNT(DISTINCT room_id) FROM events
@@ -151,7 +152,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             "count_daily_active_e2ee_rooms", _count
         )
 
-    async def count_daily_messages(self):
+    async def count_daily_messages(self) -> int:
         """
         Returns an estimate of the number of messages sent in the last day.
 
@@ -171,7 +172,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
 
         return await self.db_pool.runInteraction("count_messages", _count_messages)
 
-    async def count_daily_sent_messages(self):
+    async def count_daily_sent_messages(self) -> int:
         def _count_messages(txn):
             # This is good enough as if you have silly characters in your own
             # hostname then that's your own fault.
@@ -192,7 +193,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             "count_daily_sent_messages", _count_messages
         )
 
-    async def count_daily_active_rooms(self):
+    async def count_daily_active_rooms(self) -> int:
         def _count(txn):
             sql = """
                 SELECT COUNT(DISTINCT room_id) FROM events
@@ -226,7 +227,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             "count_monthly_users", self._count_users, thirty_days_ago
         )
 
-    def _count_users(self, txn, time_from):
+    def _count_users(self, txn: Cursor, time_from: int) -> int:
         """
         Returns number of users seen in the past time_from period
         """
@@ -238,7 +239,10 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             ) u
         """
         txn.execute(sql, (time_from,))
-        (count,) = txn.fetchone()
+        # Mypy knows that fetchone() might return None if there are no rows.
+        # We know better: "SELECT COUNT(...) FROM ..." without any GROUP BY always
+        # returns exactly one row.
+        (count,) = txn.fetchone()  # type: ignore[misc]
         return count
 
     async def count_r30_users(self) -> Dict[str, int]:
@@ -453,7 +457,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             "count_r30v2_users", _count_r30v2_users
         )
 
-    def _get_start_of_day(self):
+    def _get_start_of_day(self) -> int:
         """
         Returns millisecond unixtime for start of UTC day.
         """
diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py
index 4e1d9647b7..59bbca2e32 100644
--- a/synapse/storage/databases/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -798,9 +798,11 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         self,
         txn: LoggingTransaction,
         event_id: str,
-        allow_none=False,
-    ) -> int:
-        return self.db_pool.simple_select_one_onecol_txn(
+        allow_none: bool = False,
+    ) -> Optional[int]:
+        # Type ignore: we pass keyvalues a Dict[str, str]; the function wants
+        # Dict[str, Any]. I think mypy is unhappy because Dict is invariant?
+        return self.db_pool.simple_select_one_onecol_txn(  # type: ignore[call-overload]
             txn=txn,
             table="events",
             keyvalues={"event_id": event_id},
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index a7f6338e05..0fc282866b 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -25,6 +25,7 @@ from typing import (
     Collection,
     Deque,
     Dict,
+    Generator,
     Generic,
     Iterable,
     List,
@@ -207,7 +208,7 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
 
         return res
 
-    def _handle_queue(self, room_id):
+    def _handle_queue(self, room_id: str) -> None:
         """Attempts to handle the queue for a room if not already being handled.
 
         The queue's callback will be invoked with for each item in the queue,
@@ -227,7 +228,7 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
 
         self._currently_persisting_rooms.add(room_id)
 
-        async def handle_queue_loop():
+        async def handle_queue_loop() -> None:
             try:
                 queue = self._get_drainining_queue(room_id)
                 for item in queue:
@@ -250,15 +251,17 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
                         with PreserveLoggingContext():
                             item.deferred.callback(ret)
             finally:
-                queue = self._event_persist_queues.pop(room_id, None)
-                if queue:
-                    self._event_persist_queues[room_id] = queue
+                remaining_queue = self._event_persist_queues.pop(room_id, None)
+                if remaining_queue:
+                    self._event_persist_queues[room_id] = remaining_queue
                 self._currently_persisting_rooms.discard(room_id)
 
         # set handle_queue_loop off in the background
         run_as_background_process("persist_events", handle_queue_loop)
 
-    def _get_drainining_queue(self, room_id):
+    def _get_drainining_queue(
+        self, room_id: str
+    ) -> Generator[_EventPersistQueueItem, None, None]:
         queue = self._event_persist_queues.setdefault(room_id, deque())
 
         try:
@@ -317,7 +320,9 @@ class EventsPersistenceStorage:
         for event, ctx in events_and_contexts:
             partitioned.setdefault(event.room_id, []).append((event, ctx))
 
-        async def enqueue(item):
+        async def enqueue(
+            item: Tuple[str, List[Tuple[EventBase, EventContext]]]
+        ) -> Dict[str, str]:
             room_id, evs_ctxs = item
             return await self._event_persist_queue.add_to_queue(
                 room_id, evs_ctxs, backfilled=backfilled
@@ -1102,7 +1107,7 @@ class EventsPersistenceStorage:
 
         return False
 
-    async def _handle_potentially_left_users(self, user_ids: Set[str]):
+    async def _handle_potentially_left_users(self, user_ids: Set[str]) -> None:
         """Given a set of remote users check if the server still shares a room with
         them. If not then mark those users' device cache as stale.
         """
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index 546d6bae6e..c33df42084 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -85,7 +85,7 @@ def prepare_database(
     database_engine: BaseDatabaseEngine,
     config: Optional[HomeServerConfig],
     databases: Collection[str] = ("main", "state"),
-):
+) -> None:
     """Prepares a physical database for usage. Will either create all necessary tables
     or upgrade from an older schema version.
 
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index d1d5859214..d4a1bd4f9d 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -62,7 +62,7 @@ class StateFilter:
     types: "frozendict[str, Optional[FrozenSet[str]]]"
     include_others: bool = False
 
-    def __attrs_post_init__(self):
+    def __attrs_post_init__(self) -> None:
         # If `include_others` is set we canonicalise the filter by removing
         # wildcards from the types dictionary
         if self.include_others:
@@ -138,7 +138,9 @@ class StateFilter:
         )
 
     @staticmethod
-    def freeze(types: Mapping[str, Optional[Collection[str]]], include_others: bool):
+    def freeze(
+        types: Mapping[str, Optional[Collection[str]]], include_others: bool
+    ) -> "StateFilter":
         """
         Returns a (frozen) StateFilter with the same contents as the parameters
         specified here, which can be made of mutable types.
diff --git a/synapse/storage/types.py b/synapse/storage/types.py
index d7d6f1d90e..40536c1830 100644
--- a/synapse/storage/types.py
+++ b/synapse/storage/types.py
@@ -11,7 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Any, Iterator, List, Mapping, Optional, Sequence, Tuple, Union
+from types import TracebackType
+from typing import Any, Iterator, List, Mapping, Optional, Sequence, Tuple, Type, Union
 
 from typing_extensions import Protocol
 
@@ -86,5 +87,10 @@ class Connection(Protocol):
     def __enter__(self) -> "Connection":
         ...
 
-    def __exit__(self, exc_type, exc_value, traceback) -> Optional[bool]:
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_value: Optional[BaseException],
+        traceback: Optional[TracebackType],
+    ) -> Optional[bool]:
         ...