Files
buzz/mobile
e28707f6b2 fix(mobile): retry channel-sections startup sync when relay rate-limits cold start (#3004)
**Category:** fix
**User Impact:** Channel groups created on desktop now reliably appear
on Android and iOS on cold start, instead of falling back to the default
ungrouped list.

**Problem:** On mobile cold start, ChannelsNotifier fires ~25
per-channel REQs at once, exhausting the relay's per-connection
rate-limit quota. `ChannelSectionsManager` then gets BOTH its one-shot
history fetch and its live subscription rejected with `rate-limited:
quota exceeded` — and both errors were silently swallowed (`catch (_)`)
with no retry, so the manager kept the local (empty/default) store
forever. Restarting the app repeats the same storm, so Android reliably
lost the race every launch. Captured live on the emulator with
instrumentation.

**Solution:** Track whether the startup fetch and the live subscription
have each succeeded, and retry `_syncWithRelay` with exponential backoff
(2s base, shift-capped, 30s max) until both land. The retry timer is
cancelled on dispose, and previously-swallowed errors are now logged.

Based directly on `main` — independent of #2829 (which fixes the *write*
path: unpublished local edits being clobbered). The analogous retry for
`ChannelSortManager` lives in #2829, since that manager is introduced
there.

<details>
<summary>File changes</summary>


**mobile/lib/features/channels/channel_sections/channel_sections_manager.dart**
Extract the startup fetch + live-subscription into `_syncWithRelay`,
track success of each step, and schedule a backoff retry until both
succeed. `_fetchAndMerge` and `_startLiveSubscription` now report
success; swallowed errors are logged; retry timer cancelled on dispose.
`startupRetryBaseDelay` ctor param is test-visible.


**mobile/test/features/channels/channel_sections/channel_sections_manager_test.dart**
New regression tests with a rate-limiting relay fake: remote sections
are adopted after retries; retry stops once fetch + subscription
succeed; dispose cancels pending retries.

</details>

## Reproduction Steps

1. On desktop, create channel groups (sections) for an account.
2. Cold-start the Android app for the same account on a relay with
per-connection rate limiting and enough joined channels to trigger the
REQ burst (~25 channels reproduced it reliably).
3. Before this fix: logs show `fetch FAILED: Exception: rate-limited:
quota exceeded` and the live subscription failing, then silence — the
channel list renders the default ungrouped list forever, surviving app
restarts.
4. With this fix: logs show `startup sync incomplete; retrying in 2000ms
(attempt 1)`, the retry succeeds, and the desktop-created groups render.

## Verification

- Live on emulator-5554 (earlier stacked build of the same logic): cold
start reproduced the manager being rate-limited, then a single 2s retry
succeeding and groups rendering, matching desktop channel-for-channel.
- Full mobile suite run at this exact head (c5f1d9a38): 654 passing; the
4 failures (3× `compose_bar_test`, 1× `channels_page_test`) reproduce on
unmodified `main` (74b63e184) — pre-existing, unrelated. `flutter
analyze` clean on both touched files.

Originating thread: Buzz channel ed3994af-0949-447c-be00-29f03965b52e,
root 4bf7cbfd48bf.

---------

Signed-off-by: npub1223z34hd7vtwc6qj4s7flsxkj644nlre2nthu7lrrmkumhu3xddsrx9r6w <52a228d6edf316ec6812ac3c9fc0d696ab59fc7954d77e7be31eedcddf91335b@buzz.block.builderlab.xyz>
Co-authored-by: npub1223z34hd7vtwc6qj4s7flsxkj644nlre2nthu7lrrmkumhu3xddsrx9r6w <52a228d6edf316ec6812ac3c9fc0d696ab59fc7954d77e7be31eedcddf91335b@buzz.block.builderlab.xyz>
2026-07-27 10:43:21 -07:00
..

Buzz Mobile

Flutter mobile client for Buzz.

Setup

cd mobile
flutter pub get

Run

# From repo root (recommended — starts Docker, relay, and simulator):
just mobile-dev

# Direct (requires services and relay already running):
cd mobile && flutter run

Worktree-aware debug identity

Debug builds produced from a git worktree get a unique app identifier keyed to the worktree directory name (com.buzz.buzzMobile.<slug> on iOS, xyz.block.buzz.mobile.<slug> on Android) plus a display-only branch label in the app name (Buzz (my-branch), or a short SHA when the worktree is detached). Because the identifier follows the directory rather than the branch, one worktree keeps exactly one installed app — and its login state — across branch switches, and builds from multiple worktrees install side by side, mirroring the desktop dev experience. Release and profile builds always keep the production identity and name.

just mobile-dev and just mobile-build-android apply this automatically by running scripts/mobile-worktree-overrides.sh, which writes two gitignored files:

  • mobile/ios/Flutter/WorktreeOverrides.xcconfig (included by Debug builds only; a developer's AppOverrides.xcconfig is included after it, so app-specific overrides like a personal BUNDLE_IDENTIFIER for device signing always win)
  • mobile/android/worktree.properties (read by the debug build type only)

For direct Xcode / Android Studio / flutter run development, run ./scripts/mobile-worktree-overrides.sh from the repo root once per branch switch to refresh the display label (the install identity never changes); the persisted files are then picked up by any subsequent build. In the main checkout the script is a no-op that removes stale override files, restoring the plain Buzz identity.

To remove leftover worktree-suffixed installs from booted iOS simulators and connected Android emulators, run just mobile-clean (add --dry-run via ./scripts/mobile-worktree-clean.sh --dry-run to preview). Production installs are never touched.

Checks

dart format --output=none --set-exit-if-changed .
flutter analyze
flutter test

Or from the repo root: just mobile-check and just mobile-test.

Android release signing

Android release builds fail unless all upload-key inputs are supplied through the environment:

  • BUZZ_ANDROID_UPLOAD_KEYSTORE_PATH: path to a CI-vended keystore file
  • BUZZ_ANDROID_UPLOAD_KEYSTORE_PASSWORD
  • BUZZ_ANDROID_UPLOAD_KEY_ALIAS
  • BUZZ_ANDROID_UPLOAD_KEY_PASSWORD

The keystore path must be absolute, and the keystore must remain outside the repository. Development and debug builds do not require these variables.

Release pipelines that sign through the central APK Signer service instead of a local upload keystore must set BUZZ_ANDROID_RELEASE_SIGNING=external. That mode produces an unsigned release bundle and refuses to run if any BUZZ_ANDROID_UPLOAD_* value is also set.

Architecture

lib/
├── main.dart              # Entry point, Riverpod bootstrap
├── app.dart               # MaterialApp with theme
├── shared/
│   └── theme/             # Catppuccin light/dark, spacing tokens, extensions
└── features/
    └── home/              # Placeholder home surface
  • State management: Riverpod + Hooks (HookConsumerWidget)
  • Theme: Catppuccin Latte (light) / Macchiato (dark) — matches desktop
  • Spacing: Grid tokens for consistent spacing
  • Linting: flutter_lints + riverpod_lint via custom_lint
  • Feature isolation: No cross-feature imports except shared/