d342cf141c
## Summary
Every channel refresh path (app resume, reconnect, the backstop, joining
a channel) re-runs the unread catch-up. Each run asked for every
channel's messages since its read timestamp, up to 1000 full messages
per channel. For a reader with long-unread channels that is megabytes,
every time.
Measured on an iPhone 12 mini against the internal relay (gzip wire
bytes, instrumented profile build):
| | main | this PR |
| --- | --- | --- |
| Cold start unread catch-up | 3.5MB | 3.5MB (unchanged, first catch-up)
|
| Unread catch-up on app resume | 3.5MB | 23KB |
The 60s foreground backstop is one of those paths, so on main an open
app downloads the full catch-up again every minute (about 3.5MB a minute
on this account). With this PR each tick costs about 23KB.
On an Edge-class link (Network Link Conditioner "Edge", about 30KB/s) a
3.5MB batch needs about two minutes but has an 8s history timeout, so it
never completes and the next refresh starts it again.
A later catch-up in the same session now starts
`relayCrossDeviceSkewSeconds` (1860s) before the previous one was sent.
The relay rejects events whose `created_at` is more than 900s from its
clock, so a sender 900s slow and this phone 900s fast are at most 1800s
apart. Every message stored since the previous catch-up therefore falls
inside the window, including one that arrives late with an older
timestamp (for example, composed offline or on a phone with a slow
clock). Messages before that point were already recorded or skipped, so
unread and attention state is unchanged. The record is cleared with the
rest of the unread state when the channel list is rebuilt (community or
identity switch), and ignored if a channel's read timestamp ever moves
back. A channel whose websocket fallback filter failed (without a
deadline, so the batch still completes) is not recorded, so the next
catch-up asks for its whole window again. A deletion that removes an
unread event the app already recorded also drops the channel's record.
That event may have been the oldest of a full window of quiet agent
messages, standing in for older unread ones the window hides, and only a
whole-window catch-up finds them again. A catch-up that was already out
when that happened doesn't restore the record, since its response only
covers the narrower window. A channel muted or unmuted since its record
also catches up over its whole window, because muting changes which
messages count.
## Testing
- New test: a repeated catch-up starts 1860s before the previous one was
sent, and still records a message that arrived late with a timestamp
1500s before it. Confirmed it fails without the drift window (`since`
starts at the previous send time) and with the earlier 960s window.
- New test: a rebuilt channel list catches up over the whole window
again.
- New test: a channel whose batch and websocket fallback both failed
catches up over its whole window on the next refresh. Confirmed it fails
without the fix.
- Extended test: deleting the quiet-window marker while a catch-up is
out makes the next catch-up ask for the whole window, and the next quiet
message stands in. Confirmed it fails without each fix.
- New test: a channel unmuted since its last catch-up asks for its whole
window and records its ordinary backlog. Confirmed it fails without the
fix.
- The test fake now honors `since` and `until` like the relay. The
deletion cases now use recent timestamps, because a relay never stores a
1970 event late.
- `just mobile-check` and `just mobile-test` pass.
- Device: resumed Buzz on the 12 mini on Wi-Fi with the fix;
backgrounded for a minute, the catch-up requests were 22KB and 0.5KB
instead of 3.2MB and 287KB (f71c6c7600).
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Signed-off-by: Tom Brow <tomb@squareup.com>
Co-authored-by: Tom Brow <tomb@squareup.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Buzz Mobile
Flutter mobile client for Buzz.
See VISION_MOBILE.md for intended behavior and architecture.
Optional Builderlab login
BUZZ_AUTH_DOMAINS is a comma-separated build-time environment setting, passed
with Flutter's --dart-define (shell environment variables alone are not read):
flutter run --dart-define=BUZZ_AUTH_DOMAINS=communities.buzz.xyz,communities.public.builderlabstaging.xyz
Unset or empty means Builderlab features are disabled: no account login, community creation, backup/recovery UI, reconnect prompts, or background account restoration. QR/code pairing, community links and invites use Nostr-only entry. Saved account keys and sessions are retained for a later enabled build.
A nonempty list enables Builderlab features and requires account setup only for
matching domains. Those features need their backend endpoints. Normal relay key
authentication remains in place. BUZZ_BUILDERLAB_URL selects the backend; setting
it alone does not enable Builderlab features.
Entries match the domain itself and its subdomains, case-insensitively. Use DNS
names, not URLs or wildcards. The list does not add trusted account servers:
configured domains outside the supported Builderlab realm cannot use hosted
setup. BUZZ_BUILDERLAB_URL still selects the trusted account environment.
Hosted relay authentication
--dart-define=BUZZ_HOSTED_RELAY_AUTH=true enables Builderlab relay assertions
and reconnect sign-in only for BUZZ_AUTH_DOMAINS matches. It defaults off: configure backend assertion issuance
before enabling mobile authentication, and enable relay enforcement last.
Setup
Use the Flutter SDK pinned by the repository. Activate Hermit from the repo root before resolving packages or running any Flutter command:
cd /path/to/buzz
. ./bin/activate-hermit
./bin/just mobile-install
mobile-build-android intentionally builds with --no-pub. If an IDE or an
external Flutter SDK has touched mobile/.dart_tool, rerun mobile-install
with the pinned SDK before building so flutter_test, sky_engine, and the
engine all come from the same Flutter version.
iOS toolchain
Use Xcode 27.0 for iOS development and build validation on an Apple silicon Mac running macOS Tahoe 26.6 or later, as required by the Xcode 27 release notes. On Intel Macs or hosts that cannot meet those requirements, use a compatible Xcode 26 version, which remains supported. Activate the repository's pinned Flutter SDK with Hermit as described above.
When multiple Xcode versions are installed, select the intended version for
the command with DEVELOPER_DIR, for example:
DEVELOPER_DIR=/Applications/Xcode-27.0.0.app/Contents/Developer xcodebuild -version
Adjust the path to your installation. Keep the compiler and SDK from the same
Xcode installation. The pinned Flutter native-assets tooling can discover the
globally selected SDK even when DEVELOPER_DIR selects another compiler, so
use a build machine with a matching default Xcode when validating either
Xcode 26 or Xcode 27.
The native cryptography dependency is pinned upstream C source in
ios/BuzzPushKit/Sources/CSecp256k1; it requires no Swift build-plugin approval.
GitHub's mobile CI currently uses the Xcode default of its macos-latest
runner. The internal release toolchain is configured separately in
buzz-releases.
Run
# From repo root (applies a worktree-isolated debug identity and starts/reuses Simulator):
just mobile-dev
# Direct (uses the app's configured community; apply worktree overrides first):
cd mobile && flutter run --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example
Worktree-aware debug identity
Debug builds produced from a git worktree get a unique app identifier keyed
to the worktree directory name
(xyz.block.buzz.dev.mobile.<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'sAppOverrides.xcconfigis included after it, so app-specific overrides like a personalBUNDLE_IDENTIFIERfor device signing always win)mobile/android/worktree.properties(read by the debug build type only)
Android developers can keep a stable local test identity that takes precedence
over the generated worktree values by creating the gitignored
mobile/android/AppOverrides.properties:
appName=Buzz Pairing
applicationIdSuffix=.device_pairing_e2e1
These values are consumed by the debug build type only. The standard
just mobile-build-android command can still be used; regenerating
worktree.properties does not overwrite AppOverrides.properties. Release
and profile builds keep the production Buzz name and application ID.
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 enable push in direct Xcode builds and Runner tests, supply a
BUZZ_PUSH_GATEWAY_URL build setting in the gitignored
mobile/ios/Flutter/AppOverrides.xcconfig; the build phase validates and
passes it through as a Flutter Dart define. Since // begins an xcconfig
comment, spell the origin as BUZZ_PUSH_GATEWAY_URL = https:/$()/push.example.
For an Android debug build that must remain installed alongside other Buzz worktree builds, set an explicit launcher name and package suffix when invoking the generator or a recipe that invokes it:
BUZZ_PUSH_GATEWAY_URL="https://push.example" \
BUZZ_ANDROID_DEBUG_APP_NAME="Buzz Huddles" \
BUZZ_ANDROID_DEBUG_ID_SUFFIX=".huddles_829c" \
./bin/just mobile-build-android
This example produces the debug-only package
xyz.block.buzz.mobile.huddles_829c with the launcher label Buzz Huddles.
The suffix must start with a dot followed by a lowercase letter and may contain
only lowercase letters, digits, and underscores. Release and profile builds
ignore these overrides and retain the production package and name.
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.
iOS push capability
Every iOS artifact builds and embeds the Notification Service Extension and
native push bridge. Runtime activation is fail-closed and scoped to the current
relay. After authenticated connectivity and a fully valid NIP-11 buzz-push-v1 push
descriptor, Buzz independently requests display permission and registers with
APNs. Display denial or request failure does not gate the device token, gateway
enrollment, or lease publication, so a later user opt-in can display pushes
without rebuilding transport authority. An absent, malformed, or unreachable
descriptor leaves push inactive without partial enrollment.
Mobile builds without a gateway origin succeed with push unavailable. To enable push, supply the gateway origin explicitly:
flutter build ios --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example
flutter build apk --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example
The iOS and Android build gates validate any supplied define, rejecting empty or malformed values. Release/profile builds require an HTTPS origin without an explicit port. An absent define disables permission requests, APNs registration, gateway enrollment, and lease publication; Settings shows push as unavailable. No production gateway is selected implicitly. Enrollment grants and crash-recovery journals are scoped to this origin. Push has not shipped to existing users, so there is no legacy-state or cross-gateway migration. Changing gateways requires fresh enrollment; old installations expire under their original gateway's lease policy. Current-gateway response loss is still retried from the exact journaled request.
Relay rollout remains an explicit deployment opt-in. Only deployments with
BUZZ_PUSH_ENABLED=true advertise the descriptor and process push. See
docs/push-gateway-deployment.md for the canonical gateway profile contract,
manual physical-device proof, measurements, and rollback procedure.
For local physical-device development, override the identity and sandbox
environments in the gitignored mobile/ios/Flutter/AppOverrides.xcconfig:
BUNDLE_IDENTIFIER = com.example.buzz.mobile
BUZZ_DEVELOPMENT_TEAM = YOUR_TEAM_ID
BUZZ_IOS_PUSH_ENVIRONMENT = development
BUZZ_APP_ATTEST_ENVIRONMENT = development
BUZZ_PUSH_GATEWAY_URL = https:/$()/push.example
Use your personal bundle ID and team above. Provision both the parent and its
.NotificationService extension. Configure an isolated gateway with the matching
App Attest application ID, APNs topic and sandbox certificate. Development
attestation requires the explicit personal-dev-app-attest gateway build feature
and BUZZ_PUSH_APP_ATTEST_ENVIRONMENT=development; ordinary gateway builds accept
production attestation only. See docs/push-gateway-deployment.md.
Validate distributed builds separately using a signed release candidate and
its matching gateway configuration.
Parent app identifiers require Apple's Communication Notifications capability and a regenerated app provisioning profile. The Notification Service Extension profile does not require that capability. Enable it on the personal development App ID for local rich-presentation validation. Enabling it on distribution App IDs is a release follow-up and is not performed by this repository change. Without a matching parent profile, source and unit validation still work, but the app cannot be signed for a physical device.
APNs and the gateway continue to carry only the constant opaque wake-up. The extension fetches the message from the scoped relay, verifies message, sender profile, and channel-metadata signatures, and uses a bounded App Group cache for names and app-rendered avatar thumbnails. It never fetches an avatar URL; missing, stale, or invalid enrichment falls back to the verified message with a short sender pubkey, community subtitle, and no image.
Checks
dart format --output=none --set-exit-if-changed .
flutter analyze
flutter test --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example
Or from the repo root: just mobile-check and just mobile-test.
When writing tests, favor a few journey tests that drive real user flows over many small logic tests. See Testing Conventions.
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 fileBUZZ_ANDROID_UPLOAD_KEYSTORE_PASSWORDBUZZ_ANDROID_UPLOAD_KEY_ALIASBUZZ_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:
Gridtokens for consistent spacing - Linting:
flutter_lints+riverpod_lintviacustom_lint - Feature isolation: No cross-feature imports except
shared/