From 102677638002b3ef6ae956947333ddcde80680a7 Mon Sep 17 00:00:00 2001 From: David Robertson Date: Mon, 2 Oct 2023 15:22:36 +0100 Subject: mypy plugin to check `@cached` return types (#14911) Co-authored-by: David Robertson Co-authored-by: Patrick Cloke Co-authored-by: Erik Johnston Assert that the return type of callables wrapped in @cached and @cachedList are cachable (aka immutable). --- synapse/handlers/room_list.py | 4 +- .../storage/databases/main/event_push_actions.py | 7 ++- synapse/storage/databases/main/relations.py | 12 ++-- synapse/storage/databases/main/roommember.py | 5 +- synapse/storage/roommember.py | 1 + synapse/util/caches/descriptors.py | 64 +++++++++++++++++++--- 6 files changed, 72 insertions(+), 21 deletions(-) (limited to 'synapse') diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py index bb0bdb8e6f..36e2db8975 100644 --- a/synapse/handlers/room_list.py +++ b/synapse/handlers/room_list.py @@ -33,7 +33,7 @@ from synapse.api.errors import ( RequestSendFailed, SynapseError, ) -from synapse.types import JsonDict, ThirdPartyInstanceID +from synapse.types import JsonDict, JsonMapping, ThirdPartyInstanceID from synapse.util.caches.descriptors import _CacheContext, cached from synapse.util.caches.response_cache import ResponseCache @@ -256,7 +256,7 @@ class RoomListHandler: cache_context: _CacheContext, with_alias: bool = True, allow_private: bool = False, - ) -> Optional[JsonDict]: + ) -> Optional[JsonMapping]: """Returns the entry for a room Args: diff --git a/synapse/storage/databases/main/event_push_actions.py b/synapse/storage/databases/main/event_push_actions.py index ba99e63d26..39556481ff 100644 --- a/synapse/storage/databases/main/event_push_actions.py +++ b/synapse/storage/databases/main/event_push_actions.py @@ -182,6 +182,7 @@ class UserPushAction(EmailPushAction): profile_tag: str +# TODO This is used as a cached value and is mutable. @attr.s(slots=True, auto_attribs=True) class NotifCounts: """ @@ -193,7 +194,7 @@ class NotifCounts: highlight_count: int = 0 -@attr.s(slots=True, auto_attribs=True) +@attr.s(slots=True, frozen=True, auto_attribs=True) class RoomNotifCounts: """ The per-user, per-room count of notifications. Used by sync and push. @@ -201,7 +202,7 @@ class RoomNotifCounts: main_timeline: NotifCounts # Map of thread ID to the notification counts. - threads: Dict[str, NotifCounts] + threads: Mapping[str, NotifCounts] @staticmethod def empty() -> "RoomNotifCounts": @@ -483,7 +484,7 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas return room_to_count - @cached(tree=True, max_entries=5000, iterable=True) + @cached(tree=True, max_entries=5000, iterable=True) # type: ignore[synapse-@cached-mutable] async def get_unread_event_push_actions_by_room_for_user( self, room_id: str, diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py index b67f780c10..9246b418f5 100644 --- a/synapse/storage/databases/main/relations.py +++ b/synapse/storage/databases/main/relations.py @@ -458,7 +458,7 @@ class RelationsWorkerStore(SQLBaseStore): ) return result is not None - @cached() + @cached() # type: ignore[synapse-@cached-mutable] async def get_references_for_event(self, event_id: str) -> List[JsonDict]: raise NotImplementedError() @@ -512,11 +512,12 @@ class RelationsWorkerStore(SQLBaseStore): "_get_references_for_events_txn", _get_references_for_events_txn ) - @cached() + @cached() # type: ignore[synapse-@cached-mutable] def get_applicable_edit(self, event_id: str) -> Optional[EventBase]: raise NotImplementedError() - @cachedList(cached_method_name="get_applicable_edit", list_name="event_ids") + # TODO: This returns a mutable object, which is generally bad. + @cachedList(cached_method_name="get_applicable_edit", list_name="event_ids") # type: ignore[synapse-@cached-mutable] async def get_applicable_edits( self, event_ids: Collection[str] ) -> Mapping[str, Optional[EventBase]]: @@ -598,11 +599,12 @@ class RelationsWorkerStore(SQLBaseStore): for original_event_id in event_ids } - @cached() + @cached() # type: ignore[synapse-@cached-mutable] def get_thread_summary(self, event_id: str) -> Optional[Tuple[int, EventBase]]: raise NotImplementedError() - @cachedList(cached_method_name="get_thread_summary", list_name="event_ids") + # TODO: This returns a mutable object, which is generally bad. + @cachedList(cached_method_name="get_thread_summary", list_name="event_ids") # type: ignore[synapse-@cached-mutable] async def get_thread_summaries( self, event_ids: Collection[str] ) -> Mapping[str, Optional[Tuple[int, EventBase]]]: diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py index 3755773faa..e93573f315 100644 --- a/synapse/storage/databases/main/roommember.py +++ b/synapse/storage/databases/main/roommember.py @@ -275,7 +275,7 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore): _get_users_in_room_with_profiles, ) - @cached(max_entries=100000) + @cached(max_entries=100000) # type: ignore[synapse-@cached-mutable] async def get_room_summary(self, room_id: str) -> Mapping[str, MemberSummary]: """Get the details of a room roughly suitable for use by the room summary extension to /sync. Useful when lazy loading room members. @@ -1071,7 +1071,8 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore): ) return {row["event_id"]: row["membership"] for row in rows} - @cached(max_entries=10000) + # TODO This returns a mutable object, which is generally confusing when using a cache. + @cached(max_entries=10000) # type: ignore[synapse-@cached-mutable] def _get_joined_hosts_cache(self, room_id: str) -> "_JoinedHostsCache": return _JoinedHostsCache() diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py index 2500381b7b..cbfb32014c 100644 --- a/synapse/storage/roommember.py +++ b/synapse/storage/roommember.py @@ -45,6 +45,7 @@ class ProfileInfo: display_name: Optional[str] +# TODO This is used as a cached value and is mutable. @attr.s(slots=True, frozen=True, weakref_slot=False, auto_attribs=True) class MemberSummary: # A truncated list of (user_id, event_id) tuples for users of a given diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index 8514a75a1c..ce736fdf75 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -36,6 +36,8 @@ from typing import ( ) from weakref import WeakValueDictionary +import attr + from twisted.internet import defer from twisted.python.failure import Failure @@ -466,6 +468,35 @@ class _CacheContext: ) +@attr.s(auto_attribs=True, slots=True, frozen=True) +class _CachedFunctionDescriptor: + """Helper for `@cached`, we name it so that we can hook into it with mypy + plugin.""" + + max_entries: int + num_args: Optional[int] + uncached_args: Optional[Collection[str]] + tree: bool + cache_context: bool + iterable: bool + prune_unread_entries: bool + name: Optional[str] + + def __call__(self, orig: F) -> CachedFunction[F]: + d = DeferredCacheDescriptor( + orig, + max_entries=self.max_entries, + num_args=self.num_args, + uncached_args=self.uncached_args, + tree=self.tree, + cache_context=self.cache_context, + iterable=self.iterable, + prune_unread_entries=self.prune_unread_entries, + name=self.name, + ) + return cast(CachedFunction[F], d) + + def cached( *, max_entries: int = 1000, @@ -476,9 +507,8 @@ def cached( iterable: bool = False, prune_unread_entries: bool = True, name: Optional[str] = None, -) -> Callable[[F], CachedFunction[F]]: - func = lambda orig: DeferredCacheDescriptor( - orig, +) -> _CachedFunctionDescriptor: + return _CachedFunctionDescriptor( max_entries=max_entries, num_args=num_args, uncached_args=uncached_args, @@ -489,7 +519,26 @@ def cached( name=name, ) - return cast(Callable[[F], CachedFunction[F]], func) + +@attr.s(auto_attribs=True, slots=True, frozen=True) +class _CachedListFunctionDescriptor: + """Helper for `@cachedList`, we name it so that we can hook into it with mypy + plugin.""" + + cached_method_name: str + list_name: str + num_args: Optional[int] = None + name: Optional[str] = None + + def __call__(self, orig: F) -> CachedFunction[F]: + d = DeferredCacheListDescriptor( + orig, + cached_method_name=self.cached_method_name, + list_name=self.list_name, + num_args=self.num_args, + name=self.name, + ) + return cast(CachedFunction[F], d) def cachedList( @@ -498,7 +547,7 @@ def cachedList( list_name: str, num_args: Optional[int] = None, name: Optional[str] = None, -) -> Callable[[F], CachedFunction[F]]: +) -> _CachedListFunctionDescriptor: """Creates a descriptor that wraps a function in a `DeferredCacheListDescriptor`. Used to do batch lookups for an already created cache. One of the arguments @@ -527,16 +576,13 @@ def cachedList( def batch_do_something(self, first_arg, second_args): ... """ - func = lambda orig: DeferredCacheListDescriptor( - orig, + return _CachedListFunctionDescriptor( cached_method_name=cached_method_name, list_name=list_name, num_args=num_args, name=name, ) - return cast(Callable[[F], CachedFunction[F]], func) - def _get_cache_key_builder( param_names: Sequence[str], -- cgit 1.4.1