Files
buzz/mobile
Wes 2f3dd850db fix(relay): reject a frame on its own acknowledgement channel (#6961)
Pinky, an AI agent, updated this description on Wes's behalf after
taking over the startup investigation.

**Category:** fix

**User Impact:** An EVENT refused by WebSocket admission or handler
saturation receives a correlated `OK(event_id, false, reason)` instead
of an uncorrelated NOTICE, so the client can settle that refusal without
waiting for its publish timeout. Rate-limited refusals also arm client
backoff. This fixes a protocol failure mechanism; it does not establish
that every startup send will succeed or that the reported Desktop
startup incident is fully resolved.

**Problem:** Startup opens several live subscriptions and publishes at
once, and the relay's WebSocket admission gate is a fixed 5-second
window (`ws_admission_budget` = `human_ws_events_per_sec * 5`). If that
shared per-principal quota is exhausted, `enforce_ws_admission`
previously rejected an EVENT with a bare `["NOTICE", reason]`. Quota
pressure is a possible trigger, not proof of the original incident's
complete cause.

A NOTICE carries no event id. Both clients settle a pending publish
*only* from an `OK` keyed by event id (desktop `pendingEvents`, mobile
`_pendingEvents`), so nothing settled — and `handle_text_message`
returns early, so no `OK` ever followed either. The send **could not
fail**; it could only time out at `PUBLISH_TIMEOUT_MS` = 25s. That
explains how this rejection mechanism can produce a roughly 25-second
timeout; attributing the original report to it still requires the actual
startup/send workflow.

The handler-semaphore saturation path had the identical defect, and that
one needs no quota burst to fire.

**Solution:** NIP-01 gives each request type its own acknowledgement
channel, and a rejection is only actionable on the same one. Reject a
REQ with `CLOSED`, an EVENT with `OK(id, false, reason)`, and fall back
to `NOTICE` only where no per-request correlation exists. COUNT refusals
now also use `CLOSED(query_id, reason)` per NIP-45, covering both quota
admission and handler saturation (added in
`cd12c93804b87a24b61075dfd171dc471a0a527f`).

Reason strings are unchanged, so the `rate-limited:` prefix and `retry
in {N}s` hint that existing client gates parse keep working (desktop
`parseRateLimitHint`, mobile `RelayRateLimitGate`, buzz-acp
`set_rate_limit_gate`). Only the frame *type* changes, so
`docs/multi-tenant-relay.md` L7 stays satisfied.

Two notes on how this landed, both worth a reviewer's attention:

1. **A survived mutation became a design change.**
`send_admission_result` originally took a `RejectionTarget` parameter,
and reverting the *second* call site (the per-minute message quota)
survived the whole suite — with Redis unreachable the first quota check
short-circuits, so that line is unreachable in test. Rather than test
around it, the parameter is gone: the target is derived from the frame,
so no call site can name the wrong channel.

2. **The relay fix would have caused a client regression on its own.**
Gate arming lived only in the NOTICE branch. Once rejections arrive as
`OK:false`, `handleOk` failed the send without ever backing off — the
client would retry straight into the same quota. Desktop and Mobile now
arm on a `rate-limited:` OK rejection. ACP was subsequently fixed in
`3b06dd32493596ec650f20abf8805791c50fdc24`: it arms the gate and
re-parks only the refused observer frame, preserving other in-flight
frames. Desktop gets `activateRateLimitIfSignalled` as the single owner
of that prefix test, called from both `handleOk` and the NOTICE branch.

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

**crates/buzz-relay/src/rejection.rs** (new)
Owns the admission-rejection concern: `RejectionTarget`,
`rejection_target_for`, `request_rejection_message`,
`send_admission_result`, and `enforce_ws_admission`, moved out of
`connection.rs`. Six tests, two of which drive the real
`enforce_ws_admission` against a real `AppState`.

**crates/buzz-relay/src/connection.rs**
Fix the EVENT handler-semaphore rejection to correlate to the event id;
delegate admission to the new module. Add two tests that drive the real
`handle_text_message` with every handler permit held. Down from 1319 to
1116 lines.

**crates/buzz-relay/src/state.rs**
Widen the existing `test_state` helper to `pub(crate)` so the rejection
tests reuse it rather than adding a ninth copy of `AppState`
construction.

**desktop/src/shared/api/relayRateLimitGate.ts**
Add `activateRateLimitIfSignalled` — one owner for the `rate-limited:`
prefix test, since three inbound frame types now carry it.

**desktop/src/shared/api/relayClientSession.ts**
Arm the gate on a rate-limited OK rejection; route the NOTICE branch
through the same helper. Net zero lines, which keeps this
already-oversized file within the differential ratchet.

**desktop/src/shared/api/relayClientPublishRejection.test.mjs** (new)
Four tests against the real `RelayClient`: a rate-limited OK settles the
pending publish and arms the gate; an ordinary rejection does not arm
it; an accepted OK still resolves.

**mobile/lib/shared/relay/relay_session.dart**
Arm the gate in `_handleOk` for a rate-limited rejection.

**mobile/test/shared/relay/relay_session_test.dart**
Two tests driving the real `publish` + `debugHandleMessage` path.

</details>

<details>
<summary>Validation</summary>

**Mutation-tested — 5 mutations, all now killed.** Each production call
site was reverted to the defective behaviour to confirm a test fails.
This caught two false-negative tests:

| # | Mutation | Result |
|---|----------|--------|
| 1 | `rejection_target_for`: EVENT → `Connection` | 4 tests fail |
| 2 | EVENT handler-semaphore call site → bare NOTICE | **survived at
first** |
| 3 | per-minute quota call site → `Connection` | **survived**; fixed by
removing the parameter |
| 4 | desktop `handleOk` gate arming removed | 1 test fails |
| 5 | mobile `_handleOk` gate arming removed | 1 test fails |

Mutation 2 is the lesson: my first saturation test called
`request_rejection_message` directly, so reverting the real call site
inside the `match` arm left it green. It now drives
`handle_text_message` itself and dies on that mutation.

- `cargo test -p buzz-relay` — 928 passed, 1 failed:
`api::mesh_demo::tests::demo_join_forwarded_arm_round_trips_echo`,
**pre-existing**, reproduced with all changes stashed at `4dd4d73de`.
- `cd desktop && npm test` — 5721 passed, 0 failed (full suite).
- `cd mobile && flutter test` — 1876 passed, 0 failed (full suite).
- `just fmt-check`, `just clippy`, `just desktop-check`, `just
mobile-check`, `just file-size-check` — clean. Desktop's 5 biome
warnings are pre-existing (reproduced with changes stashed).
- All 9 pre-push lanes green, including `rust-tests` and
`desktop-tauri-checks`.

**Not verified:** not reproduced end-to-end against a live relay under a
forced quota burst. The causal chain is source-proven and
mutation-proven at the frame level; the ~25s attribution follows from
`PUBLISH_TIMEOUT_MS` but is not directly measured. A packaged-build
click-through would close that gap.

</details>

Related work: #6957 bounds Desktop HTTP event submission, but safe
retained-operation recovery after exhausted/ambiguous outcomes remains
unfinished. #6998 is the separately reviewable Desktop
readiness/duplicate-subscription slice. Neither is claimed to complete
native before/after startup-send validation.

Diagnosis note: `RESEARCH/DESKTOP_STARTUP_SEND_STALL_2026_08_27.md`
(Brain's workspace).

## Current review disposition (2026-08-28)

The [review on
`cd12c938`](https://github.com/block/buzz/pull/6961#pullrequestreview-5052902510)
identified ACP's missing rate-limited-OK handling. Commit
`3b06dd32493596ec650f20abf8805791c50fdc24` fixes gate arming, re-parking
the specifically refused observer frame, and the stale NOTICE comment.
Two regressions drive the real frame dispatcher. See [the implementation
and validation
response](https://github.com/block/buzz/pull/6961#issuecomment-5455032054).

The Mobile generation-check inline thread is resolved: its `async
publish` returns a failed Future when superseded; it does not throw
synchronously at invocation. No further production change was indicated
by that comment.

The validation counts above describe the original slice, not a new
rerun. At `3b06dd324`, the current GitHub check rollup has successful
completed test/build checks (non-applicable jobs skipped). The
security-review comment still requires review for the current base/head
range; do not read a green authorization job as a completed security
review. Approval and merge remain human decisions.

---------

Signed-off-by: Brain <1a02c72794dcd0f07058a353bc3a81f4028b8c77c92c87fce6d5c8b85970a20b@buzz.block.builderlab.xyz>
Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Brain <1a02c72794dcd0f07058a353bc3a81f4028b8c77c92c87fce6d5c8b85970a20b@buzz.block.builderlab.xyz>
Co-authored-by: Carl <9d00794d3df50972eb8b615511783cab12a77a8fd5dd5edd58073ec73b54bd8b@buzz.block.builderlab.xyz>
2026-08-31 14:43:31 -06:00
..
…

Buzz Mobile

Flutter mobile client for Buzz.

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.

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

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.dogfood.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'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)

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.

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_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 nip-pl 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.

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 = xyz.block.buzz.mobile
BUZZ_DEVELOPMENT_TEAM = EYF346PHUG
BUZZ_IOS_PUSH_ENVIRONMENT = development
BUZZ_APP_ATTEST_ENVIRONMENT = development

This exercises the client, extension, relay, and gateway integration without requiring a dogfood development signing identity. It uses the canonical gateway's server-owned App Store profile configured for sandbox in the local development gateway; it does not validate the internally distributed dogfood artifact or enable the App Store profile in production. Validate dogfood APNs end to end by cutting an internal release, waiting for it to reach Mobile Releases/Comp Portal, and installing that signed artifact on a physical device.

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 the Block dogfood and eventual App Store 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

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/