A deep investigative review of the export concurrency (four parallel adversarial
reviewers) found that three rounds of race fixes had been chasing the wrong bug, and
that the model itself was the root cause. This replaces the model and fixes the real
data loss.
THE ACTUAL BUG (upload path, not the state machine)
`upload` checked `uploads_locked_at` BEFORE streaming the body — minutes, for a large
video — then committed the row without re-checking. A release landing mid-upload let the
row commit AFTER the export snapshot: the photo appeared in the live feed and was
PERMANENTLY missing from the keepsake, with nothing to regenerate it. release_gallery's
comment claims to prevent exactly this; it never did. Every prior round fixed the DB
state machine, and the leak was upstream of it.
Fix: re-assert the lock under `SELECT ... FOR SHARE` INSIDE the commit tx. That row lock
conflicts with release_gallery's `UPDATE event`, so either the upload commits first (and
the release — hence the snapshot — is ordered after it) or the release wins and the
upload is rejected as `uploads_locked` (reversible; the client keeps the blob).
Regression test verified NON-VACUOUS: with the fix reverted it fails, reporting accepted
uploads missing from the keepsake.
THE MODEL (migration 014)
"Which generation is current?" had no single answer: it was assembled from three
separately-written pieces across two tables (`export_released_at`, a per-job
`release_seq`, and cached `export_{zip,html}_ready` flags). Keeping them in agreement
took ~10 hand-written guards; each review round found one more path that slipped through.
Now: ONE monotonic `event.export_epoch`, bumped in the same UPDATE as any change to
`export_released_at`. Each job carries a copy. Downloadable IFF
`released AND job.epoch = event.export_epoch AND status = 'done'` — readiness DERIVED,
never stored. A retired-epoch worker is INERT BY CONSTRUCTION: losing a race can no
longer corrupt state, only waste work.
Deleted: both ready-flag columns, both ready-flip blocks, `if ready { continue }`, the
reopen seq-bump, open_event's transaction, and the cross-table claim guard.
That last one was also UNSOUND: under READ COMMITTED, a blocked UPDATE re-evaluates its
WHERE against the updated target row but answers subqueries on OTHER tables from the
original snapshot — so the previous `EXISTS (SELECT ... FROM event ...)` claim guard
could admit a claim against an already-reopened event while RETURNING the post-bump seq.
Every guard is now same-row (`epoch = $n`), which EPQ re-evaluates correctly.
OTHER REAL DEFECTS FIXED
- release_gallery committed the release and THEN awaited the enqueue inside the handler
future. Axum drops that future on client disconnect → event released, uploads locked,
ZERO export_job rows, host unable to retry ("bereits freigegeben"), restart-only
recovery. Now one tx; workers spawn (detached) after commit.
- No flush/fsync before the tmp→final rename. async_zip's close() never flushes the inner
file and tokio's File drop DISCARDS write errors — so a full disk silently produced a
truncated archive that was then marked done and published, after which the last good
generation was pruned. Now flush + sync_all, which also surfaces ENOSPC.
- Download read the ready flag and the file path in TWO queries; a reopen between them
served a keepsake that should 404. Now one read through the `export_current` view.
- `if !src.exists() { continue }` then `open()?` — a TOCTOU that turned a tolerated gap
into a hard failure of the ENTIRE keepsake (unretryable while released). Now open-first,
warn, and skip.
- Recovery was flag-driven and never checked the disk: a `done` row whose archive was gone
was a permanent dead end needing manual DB surgery. Now verifies the file and re-arms.
- Temp files/dirs leaked on every error path (the leak is what fills the disk that
corrupts the next archive). Now cleaned up.
- Export archives were not event-scoped (`viewer_tmp_` already was), so a second event
would collide on paths and one event's prune would delete another's live keepsake.
- Host deletes after release never regenerated the keepsake — a photo removed on request
lived on in the archive forever. Now bumps the epoch and rebuilds without it.
- claim_job swallowed DB errors as "someone else won", stranding a job pending at 0%.
- export_status reported retired-epoch rows (a progress bar that never moves).
- The startup sweep's single-instance assumption is now documented, not hidden.
Verified: backend 40 tests, svelte-check 0 errors, e2e typecheck clean,
e2e 160 passed / 1 skipped on chromium-desktop (incl. 2 new regressions; the
upload-acceptance one confirmed to fail without the fix).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Follows the perf + security + user-flow work with a role/persona audit (guest, host,
admin, projector) and fixes across three review rounds. Highlights:
HIGH
- Ban now replays on reconnect. A ban isn't a soft-delete, and the `user-hidden` SSE has
no replay, so a client that missed it (esp. the unattended diashow) kept cycling a
banned user's slides. New `uploads_hidden_at` (migration 013) + `hidden_user_ids` in
/feed/delta; feed + diashow evict those users. Applied even on a truncated delta.
MEDIUM
- Locked-upload data loss: a photo staged offline during a lock/release was purged as a
terminal 4xx and lost when the host reopened. New reversible `uploads_locked` error code;
the queue keeps the blob and auto-resumes on the `event-opened` SSE.
- Reopen after release now warns (ConfirmSheet) that it revokes the published keepsake.
- Host "forgotten-PIN" badge updates live (`pin-reset-requested` was broadcast but never
in KNOWN_EVENTS / subscribed); host page also refetches on `pin-reset` so a two-host
race can't hand out a conflicting PIN.
- Ban modal copy fixed (read-only ban, not "session ended"); Degradieren/Sperren/Entsperren
hidden on peer-host rows for non-admins (they always 403'd).
- Host dashboard shows live keepsake generation progress / ready state + link to /export.
- Admin JWT moved to sessionStorage (§11.1) to bound exposure on shared devices.
Export generation guard (H1 from the prior round, hardened): per-(event,type) `release_seq`
(migration 012) with seq-guarded claim/finalize/mark_failed/update_progress, per-generation
temp/final paths, download follows `file_path`, prune only strictly-older generations.
LOW: diashow coalesces upload-processed (avoids self-rate-limit); event-closed reconciles
galleryReleased; /recover gains a forgot-PIN request + drops a stale cached PIN on 401;
delta `>=` tie-break + 429 retry; misc copy/labels.
Adds e2e: ban-replay, upload-lock-code, and rewrites export-reopen-rerelease with a
data-completeness test. Reconciles USER_JOURNEYS §9/§11.
Verified: cargo build clean, 40 unit tests, svelte-check 0 errors, 33 frontend unit
tests, 155 e2e passing on chromium-desktop.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
H1: auth extractor re-reads the live user row — trusts the DB role (not the
JWT claim) and rejects banned users mid-session. e2e proves a demoted
host loses powers and a banned host is locked out and can't self-unban.
H2: client_ip takes the right-most XFF hop (the one Caddy appends); spoofed
left-most entries are ignored, restoring IP-based throttles.
H3: Caddy excludes /api/v1/stream from `encode` so SSE isn't buffered.
H4: upload — quota increment + row insert + hashtag links now one txn.
H5: feed keyset pagination tiebroken on (created_at, id) + composite index
(migration 010); feed_delta bounded with LIMIT.
H7: LightboxModal keys its comment load off upload.id, ending the
SSE-driven refetch storm.
H8: CSP via SvelteKit kit.csp (svelte.config.js) hardens the localStorage
token model against injection.
Migration 010 also adds the latent comment/comment_hashtag indexes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Foundations for the v0.16 features. No new endpoints here — those land in
the next commit on top of these.
- migrations 008 + 009: commit the load-bearing compression_status column
that was uncommitted on disk; add 009_feature_toggles seeding the master
+ per-endpoint rate-limit switches, the master + per-area quota switches,
and the admin-editable privacy_note.
- services/config.rs (new): get_str / get_i64 / get_usize / get_f64 / get_bool
consolidating the scattered helpers that lived in three handlers.
- services/maintenance.rs (new):
- startup_recovery() — resets compression_status='processing' and
export_job.status='running' rows orphaned by a previous crashed
instance, so users never see permanent "Wird vorbereitet…" spinners.
- spawn_periodic_tasks() — hourly cleanup of expired sessions (rows
were never pruned) + rate-limiter HashMap pruning (windows kept one
entry per IP forever).
- services/jobs.rs (new sketch): BackgroundJob trait + JobContext for
future jobs to plug into the same progress + SSE pipeline as
compression/export. Not wired yet — codifies the convention.
- services/compression.rs: 120s hard timeout + kill_on_drop on ffmpeg
so a malformed video can't hang and leak a worker semaphore permit.
- services/rate_limiter.rs: new prune() called from the periodic task.
- state.rs: SseEvent::new() constructor so event-type strings stay
consistent instead of being typed inline at every emit site.
- models/user.rs: UserRole::as_str() for /me/context serialization.
- models/upload.rs: soft_delete() now runs in a transaction and
decrements the uploader's total_upload_bytes (GREATEST(0, …) guard) —
fixes a quota drift where deleting reclaimed no quota.
- Cargo.toml + Cargo.lock: add `infer = "0.15"` (multipart MIME sniffing
used by the upload handler).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- PROJECT.md, README.md, TEST_GUIDE.md: status line refreshed; rate-limiter
doc-vs-code drift fixed; HTML export section rewritten for the SvelteKit-
static viewer; SSE event names + new events documented; config seed block
extended with planned toggles + privacy_note; decision log entries added.
- docs/CONCEPT_HTML_VIEWER.md, docs/CONCEPT_MOBILE_UI.md: banner the design
intent as shipped; point at the source-of-truth code paths.
- docs/CONCEPT_DIASHOW.md: planned-then-shipped design for the live diashow
(two-queue policy, pluggable transitions, data-mode aware).
- docs/FEATURES.md: capability matrix by role (Guest / Host / Admin) plus
prose per area (auth, posting, feed, moderation, admin, export, gestures,
data mode, quotas, privacy note, extensibility).
- docs/USER_JOURNEYS.md: step-by-step flows for every supported scenario,
including PIN reset by host, data mode, privacy note, gestures, and the
admin toggles.
- docs/IDEAS.md: speculative extensions (global diashow, reactions,
multi-tenancy, animation pack, etc.) — explicitly out of v0.16 scope.
- backend/migrations/README.md, frontend/src/lib/README.md: codify the
"never edit a shipped migration" rule and the lib/ conventions
(one store per concern, gestures via actions, sheets via ContextSheet,
transitions as drop-in components).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Backend: migration 007 adds a case-insensitive unique index on user names
per event. join endpoint returns 409 conflict when the name is taken.
find_by_event_and_name uses LOWER() for case-insensitive recovery.
Frontend: join page handles 409 with a name-taken view — amber warning,
name-choice tips, inline PIN recovery form, and "Anderen Namen wählen"
button. Test guide updated with Steps 8 and 9.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Backend:
- AppConfig, AppError, AppState modules for shared infrastructure
- JWT creation/verification with HS256 (jsonwebtoken crate)
- Session management: SHA-256 token hashing, DB-backed sessions
- Auth middleware: AuthUser, RequireHost, RequireAdmin extractors
- POST /api/v1/join: name-only registration, 4-digit PIN + bcrypt hash
- POST /api/v1/recover: PIN-based recovery with 3-attempt lockout (15 min)
- POST /api/v1/admin/login: bcrypt password verification
- DELETE /api/v1/session: logout (session invalidation)
- Migration 006: user PIN lockout columns (failed_pin_attempts, pin_locked_until)
- Models: Event, User (with role enum), Session with all CRUD methods
Frontend:
- api.ts: typed fetch wrapper with automatic Bearer token injection
- auth.ts: JWT/PIN localStorage management with Svelte store
- /join: name entry form with PIN display modal and copy button
- /recover: name + PIN recovery form with saved PIN pre-fill
- /feed: placeholder gallery page with logout
- Root layout: auth initialization on mount
- Root page: redirect to /join or /feed based on auth state
All responses use German language strings as specified.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
