Files
buzz/mobile/test/features/channels/channel_sections
Will Pfleger 309e34d80f fix(mobile): converge sidebar managers on relay head with resume re-read (#7806)
Mobile half of the sidebar stale-reader fix (desktop: #7805). It makes
the channel sections, sort, stars and mutes managers converge on the
latest relay head.

## Changes

- **Tie-break:** sections, stars and mutes compare `(created_at, id)`
with `id < cursor`, which matches the relay's `ORDER BY created_at DESC,
id ASC`. Sort already did this.
- **Coherent cursor:** `_publish()` records the signed event ID through
`SignedEventRelay.submit(onSigned:)` and advances
`(_lastRemoteCreatedAt, _lastRemoteEventId)` together. It only advances
when the pair is after the current cursor, so a newer head learned
during the await is kept. This applies to sections, stars and mutes.
- **Stars/mutes startup retry:** one serialized `_syncWithRelay()`
(`_syncInFlight`/`_syncAgain`) with 2s→30s backoff. It retries until the
history head is applied and the live subscription is settled. The
stars/mutes managers no longer re-subscribe on CLOSED:
`RelaySessionNotifier` owns retryable and rate-limited CLOSED, and a
terminal CLOSED is never re-sent. Reconnect works through session replay
and provider rebuild. Sections and sort keep their existing manager
CLOSED retry.
- **Stars/mutes durability:** storage `write()` returns the
`setString()` result. A decode or apply error, or a persist that returns
false or throws, fails the attempt. The accepted head only advances once
it is durable, so the same head is retried.
- **Stars/mutes pending fence:** each read snapshots `_localRevision`
and `_publishPending`. If a local edit or a publish happened while the
read was in flight, the result is discarded. Startup recovery retries
it; a resume read does not. Per-entry arbitration is unchanged.
- **Sections publish commits content with its cursor:** the submitted
blob is committed together with its cursor, so a same-second loser
applied during the OK wait can't strand the device. A local edit made
during the wait is kept.
- **Stars/mutes undecodable head:** an undecodable head is skipped
without holding startup open. Only a persist failure keeps the head
unapplied and retried.
- **Resume re-read:** all four providers listen to
`appLifecycleProvider`. On `resumed`, each manager runs one guarded
history read through its existing fetch/apply path. It is one-shot:
skipped when a local edit or publish is pending as it starts, not
retried on failure, and it starts no timers or poll loop. The result is
discarded if a mutation lands before it applies, and a disposed or
superseded manager (sort generation fence) never persists it.

## Residuals

- If the app stays in the foreground the whole time and a healthy socket
drops an EVENT, the missed head is picked up on the next resume or
reconnect.
- Sections: a live event can still overwrite a pending local edit. This
is pre-existing, and the resume read adds no new path to it.
- Sort: a greater remote timestamp wins, by policy.
- Stars/mutes: entries with equal `updatedAt` can still resolve
differently on different clients, under the existing merge policy.
- Stars/mutes: publish reads first and keeps the entry with the later
`updatedAt`, so a peer whose clock runs fast can override a pending
local entry. This rule already exists on main and matches desktop.
- Sections and sort persistence failures are pre-existing and not
redesigned here.

## Size

Production: 10 files, +495/−162. Tests: 3 files, +718. The new
`sidebar_sync_fixture.dart` runs over the real `RelaySessionNotifier`
seam and is shared by `channel_reader_recovery_test.dart`. Plus a
sections tie-break case.

---------

Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
Co-authored-by: Hayt <211b96e6a2b7f45fd4047988976c7bbbeeda0c15f3ae7b32eec20834b5a55118@buzz.block.builderlab.xyz>
2026-09-24 10:16:14 -06:00
..