feat(pinned events): persist the pinned events timeline by bnjbvr · Pull Request #6085 · matrix-org/matrix-rust-sdk

bnjbvr · 2026-01-29T16:00:58Z

This brings some nice benefits:

reloading the previous list of pinned events from storage, which gives us…
…offline access for pinned events
better support for automatic redecryption of pinned events

Some important design points:

the pinned events linked chunk does include relations to pinned events, i.e. they're appended to the chunks as they show up from other sources (sync/backpaginations). This is different from the thread linked chunks, which don't, and should likely be uniformized towards that, in the future.
pinned events are first reloaded from storage, upon creation of the pinned event cache (lazily, when subscribing to pinned events for the first time); then, reloaded from network if needs be; then, updated over time, by a background task in the pinned event cache.
The task is never killed, at the moment. Ideally, it would be killed whenever there are no more listeners to the pinned events cache for this room. We should implement this in a soon future.
Lots of code duplication with the storage of linked chunks in the case of the room. To be deduplicated soon™.

Part of #5954.

codspeed-hq · 2026-02-02T17:43:39Z

Merging this PR will not alter performance

✅ 50 untouched benchmarks

_{Comparing bnjbvr/pinned-events-linked-chunk (d277d9e) with main (9ad7cf9)}

codecov · 2026-02-04T18:35:06Z

Codecov Report

❌ Patch coverage is 78.07933% with 105 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.81%. Comparing base (9ad7cf9) to head (d277d9e).
⚠️ Report is 16 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...s/matrix-sdk/src/event_cache/room/pinned_events.rs	74.79%	67 Missing and 25 partials ⚠️
crates/matrix-sdk/src/room/mod.rs	68.42%	5 Missing and 1 partial ⚠️
crates/matrix-sdk-common/src/serde_helpers.rs	80.00%	0 Missing and 3 partials ⚠️
crates/matrix-sdk/src/event_cache/room/mod.rs	89.65%	0 Missing and 3 partials ⚠️
...rates/matrix-sdk-ui/src/timeline/controller/mod.rs	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6085      +/-   ##
==========================================
- Coverage   89.88%   89.81%   -0.08%     
==========================================
  Files         363      363              
  Lines      100129   100479     +350     
  Branches   100129   100479     +350     
==========================================
+ Hits        90004    90246     +242     
- Misses       6621     6695      +74     
- Partials     3504     3538      +34

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poljar

Alright, I left some comments. Most of them are minor so I'll approve ahead of time.

crates/matrix-sdk/src/event_cache/room/mod.rs

crates/matrix-sdk/src/event_cache/room/pinned_events.rs

crates/matrix-sdk-ui/src/timeline/tasks.rs

poljar · 2026-02-05T09:59:56Z

crates/matrix-sdk-ui/src/timeline/tasks.rs

+                    // Only handle the remote aggregation for a non-live timeline, that's not the
+                    // pinned events one (since this one handles its own remote events diffs).


I'm not sure that this is needed for pinned events.

Hmm, I thought the live update task wouldn't be needed for the pinned events timeline, but that's actually unclear; it might be that the member profiles updates are still useful for such a timeline. Will defer this to a subsequent PR, and fix the comment in the meanwhile.

crates/matrix-sdk-ui/tests/integration/timeline/pinned_event.rs

crates/matrix-sdk/src/event_cache/room/pinned_events.rs

crates/matrix-sdk/tests/integration/room/pinned_events.rs

Now that this logic has moved to the event cache, it's not required in the timeline anymore.

… configure the event cache

…rovider trait And get rid of the `PinnedEventsRoom` trait, and the accompanying file.

…ions` now that it's widely available

…ache

bnjbvr · 2026-02-05T13:44:22Z

Clearing the other review requests, since Damir has reviewed this. Thanks!

…ed events task

jmartinesp · 2026-02-05T14:27:20Z

We might want to delay merging this, I found an issue while testing it with EXA where after clearing the cache, some rooms with just 1 pinned event incorrectly displays several of them.

…cache There were two issues: - first, `load_or_fetch_event_with_relations()` allowed to pass a filter, but the filter wasn't taken into account when fetching relations from the network. This would cause the initial load of pinned events to also include thread responses, which we don't want. - similarly, when adding related events from sync, we'd only look if an event had a `m.relates_to` field; but it could be a thread response being added in live. The two issues are fixed similarly, by using a new `extract_relation` serde helper that gives both the related_to event and the relation type. That way, we can apply a manual filter in `load_or_fetch_event_with_relations` after fetching relations from network, and we can filter out live events based on the relation type.

jmartinesp · 2026-02-05T15:18:15Z

The latest changes fix the previously found issue 🥳 !

bnjbvr force-pushed the bnjbvr/pinned-events-linked-chunk branch from d6a6eed to 046adb4 Compare February 2, 2026 17:20

This was referenced Feb 3, 2026

refactor(pinned events): move pin_event/unpin_event from the Timeline to the Room #6106

Merged

refactor(room): move PinnedEventsRoom::load_event_with_relations to the Room object #6108

Merged

bnjbvr force-pushed the bnjbvr/pinned-events-linked-chunk branch 5 times, most recently from fb23758 to 7f1f465 Compare February 4, 2026 18:24

bnjbvr marked this pull request as ready for review February 4, 2026 18:24

bnjbvr requested a review from a team as a code owner February 4, 2026 18:24

bnjbvr requested review from stefanceriu and removed request for a team February 4, 2026 18:24

poljar mentioned this pull request Feb 4, 2026

UTDs on pinned messages are not retried after key is received #5798

Closed

Hywan self-requested a review February 5, 2026 07:39

richvdh linked an issue Feb 5, 2026 that may be closed by this pull request

UTDs on pinned messages are not retried after key is received #5798

Closed

poljar approved these changes Feb 5, 2026

View reviewed changes

bnjbvr added 12 commits February 5, 2026 14:38

feat(linked chunk): add a new ID for the pinned events linked chunk

314a9d6

feat(event cache): add a cache for a room's pinned events

59e55f9

feat(timeline): subscribe to the pinned event cache from the timeline

0e9b863

refactor(timeline): start removing unused stuff in the timeline code

77f5001

Now that this logic has moved to the event cache, it's not required in the timeline anymore.

feat(event cache): add a global EventCacheConfig struct to globally…

cde22ea

… configure the event cache

refactor(event cache): using proper locking for the pinned event cache

9aeb3cf

refactor(timeline): move load_event_with_relations to the RoomDataP…

6372be7

…rovider trait And get rid of the `PinnedEventsRoom` trait, and the accompanying file.

refactor(event cache): use the `Room::load_or_fetch_events_with_relat…

e8db5b0

…ions` now that it's widely available

chore: address typos and cosmetic changes in an integration test

3e6719c

feat(event cache): add support for redecryption in the pinned event c…

c06717e

…ache

feat(event cache): reload the pinned event cache at startup \o/

4ccbd88

test(event cache): declare victory \o/

9a87de4

bnjbvr removed request for Hywan and stefanceriu February 5, 2026 13:44

bnjbvr added 2 commits February 5, 2026 15:13

refactor(event cache): address review comments from 6085

187eed6

refactor(event cache): use the background job monitoring for the pinn…

595e6cc

…ed events task

bnjbvr force-pushed the bnjbvr/pinned-events-linked-chunk branch from 7f1f465 to 595e6cc Compare February 5, 2026 14:18

bnjbvr enabled auto-merge (rebase) February 5, 2026 14:22

bnjbvr disabled auto-merge February 5, 2026 14:30

refactor(common): use ruma's RelationType in the extractor functions

d277d9e

bnjbvr merged commit 80920e9 into main Feb 5, 2026
53 checks passed

bnjbvr deleted the bnjbvr/pinned-events-linked-chunk branch February 5, 2026 15:43

		// Only handle the remote aggregation for a non-live timeline, that's not the
		// pinned events one (since this one handles its own remote events diffs).

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bnjbvr commented Feb 5, 2026

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