Two ways round 6's own fixes did not bound what their comments said they bounded.
The reclaim budget's window anchor was written only where the window RESET, so it marked the window's
start rather than the last loss — a tumbling window, not the rolling one the constant is named for.
Any loss cadence slower than half the window satisfied the reset on every second loss, so the budget
never reached its bound: measured over 200 loss cycles, 61/70/90/119s apart all gave 200 reclaims and
never an error, while 5s and 30s apart correctly gave two and then the honest answer. The failing
band is exactly the case the ERROR handler names — a transcode that falls behind realtime — and both
committed tests spaced their losses 0s and 10min apart, i.e. outside it. The anchor now moves with
every loss.
And `finish`'s refusal handler lowered the play-through latch, which is the only gate on the 10s
interval, the page-hide beacon and `settle`. All three post `absRef`, which on the play-to-the-end
path IS the end of the media, and the backend reads a position within `_FINISH_MARGIN_S` of the
duration as a finish — so within ten seconds of the toast saying the mark had failed, the item was
marked watched, its position cleared and a scrobble sent to Plex. Round 6 closed the explicit
rollback write and left the other three open; the test it added set `upNext: false`, which tears the
effect down before any of them can fire. The refusal now takes back the CLAIM rather than the latch:
a second flag stops `settle` re-asserting watched, and playing again clears both.
`FINISH_MARGIN_S` duplicated the backend's constant in a second language with nothing relating them,
and its comment had the asymmetry backwards — if the BACKEND's margin grows, this guard starts
admitting a rollback the backend reads as a finish, i.e. re-opens the defect above. Pinned by a
contract test that reads the Python, and the comment corrected.
`MAX_SESSION_RECLAIMS` was cleared by the first fragment of any session, and a
reclaimed session essentially always delivers one — `start_session` does not
return until its first segment exists. So the budget only ever bit where a
session parsed its manifest and then died before a single fragment, which is not
either case its own comment names. Measured: 40 loss cycles produced 41 sessions
and never an error. A transcode falling behind realtime, or two viewers of one
rating_key taking turns, respawned ffmpeg indefinitely — the round-5 behaviour,
still there behind the guard added to stop it.
It counts within a rolling window now. Two losses inside two minutes is a
session that keeps being lost; one an hour apart is not. And the window is reset
per item, because the player stays mounted across a queue advance — otherwise a
budget spent on one episode would deny the next its first legitimate reclaim.
Separately: `finish`'s rollback re-performed the write it was taking back. On
the play-to-the-end path the position it restores IS the end of the media, and
the backend reads a position within its finish margin as a finish — so the
branch named "take the finish back" set watched, cleared the position and
scrobbled to Plex through a second route, while the caller's error toast was
already on screen saying the mark had failed. There is no resume point at the
end of the media to restore; the cache drop is the whole of the rollback there.
The credits-skip caller captures a mid-episode position and still restores it,
which is the case that needs it.
7 tests, mutation-checked: the FRAG_LOADED reset, the missing window, and the
unguarded rollback each red on the test that names them.
Deep-review round 5, over round 4's own fixes.
- Round 4 added a `finish` latch so a played-through item records no checkpoint at the credits.
On a NATURAL play-through it was raised a beat too late: per the HTML spec the browser sets
`paused` and fires 'pause' BEFORE 'ended', so the pause checkpoint went out while the latch was
still down and raced the watched mark — both requests read "not watched yet" from their own
snapshot, so Plex counted one watch twice, and where Plex's reported duration runs more than the
finish margin past the real media the checkpoint wrote a resume position AFTER the scrobble. The
pause that ends the media no longer flushes. The regression test that was meant to cover this
modelled the end as a bare 'ended' event — a browser that does not exist — and is now the real
order.
- The watched mark was fired and forgotten (`.catch(() => {})`) while the latch patched the cached
detail to watched / position 0 regardless, and round 4's once-per-id start guard meant the
corrected detail arriving later was never used: an episode whose mark failed reopened at 0:00
with a Watched badge the server disagreed with. `finish` now takes the in-flight write and takes
itself back if the server refuses it — the real position is reported, the lying cache entry is
dropped, and the failure is said out loud instead of swallowed. Both callers (the natural end
and the credits auto-skip) hand it over.
- The reclaim of a 404'd HLS session had no bound. `parsed` cannot provide one — it belongs to one
hls instance and every restart builds a fresh one — and the server answers 404 both for "the
session is gone" and for "that segment is not there yet", so a transcode falling behind realtime,
or two viewers of one item taking turns, respawned ffmpeg forever behind a spinner that never
became an error. Two consecutive reclaims, reset by the first fragment that actually loads, then
the honest failure.
Five regression tests, each mutation-checked red on the assertion it is named after.
Deep-review round 4, the Plex player.
- A 404 on an HLS session that WAS playing means the server reaped it (a long pause, a deploy);
hls.js never retries a 4xx, so playback ended with "couldn't play". A new session at the playhead
now takes its place (the frontend half of the paused-viewer reap fix). A session that 404s before
its manifest is still a plain failure, so it cannot restart itself in a loop.
- Leaving an item that ended, or that the credits auto-skip left, sent a final checkpoint at the
credits (racing the watched mark, and pushing a resume point to Plex after the scrobble) and
patched "new, at 49:55" into the cache — Prev reopened it at its last seconds. `finish` settles it
as watched at 0, said before the pause whose own checkpoint could land first.
- An audio switch, an A/V offset change and every seek control read `abs`, which is 0 until
playback ticks: a resume at 20:00 restarted from 0:00. They use the shared `playhead`.
- A seek while a restart is pending always restarts (the old media's `seekable` described the old
session, and the pending answer overrode the newer seek).
- A superseded direct-play session's loadedmetadata/canplay are generation-gated and detached (they
seeked the next item to the previous one's resume point).
- The session starts once per item: a reconnect refetch, the info panel's watched toggle or a
language switch no longer restarts the film at the last checkpoint.
- Tests for the session generation's failure paths and the item-change bump, which had none.
Deep-review round 3 of bug hunt 2026-09.
- loadSession checks, after its await, that it is still the newest call and the player is still
mounted. A late answer used to replace what was playing (Next twice quickly: the slower transcode
landed last and played the middle item under the last one's title, recording its progress there)
or attach a stream to the detached <video> after Back, never destroyed.
- The <video>'s clock is trusted only once the new session has answered. go()'s pause() fires a
timeupdate AFTER the reset to 0 (measured in Chrome), so the previous item's position was sent as
the next item's subtitle position and saved as its progress (final, pushed to Plex).
- Next settles the item being left (final checkpoint + reopen-cache patch) before switching: the
progress cleanup ran with the position already reset and skipped, so every Next dropped the last
stretch watched.
- A seek-restart puts its target into the position state too; the ref alone was re-synced back to
the pre-seek spot by the restart's own render.
- The unmount teardown captures the <video> at mount: React detaches refs before an unmount's
cleanups, so the stop/detach never ran.
- The tracks panel exposes the selected audio/subtitle track via aria-pressed.
Verified in real Chrome on localdev (Westworld S1E6 → Next): the item left was settled at 783 s, the
next asked for subtitles at its own start (0), and no progress was written for it.
Deep-review round 3 of bug hunt 2026-09.
- `failed` is now final only for a track that can never be text (bitmap, no item/track/file). A Plex
hiccup or a stretch ffmpeg could not read answers `unavailable`: said, polled again every 5 s, and
the <track> stays mounted when cues exist elsewhere (gen > 0). Re-picking the selected track asks
the server again at once.
- Within LOOKAHEAD_S of a covered stretch's end the next window is read ahead, instead of only once
the playhead has fallen off it (subtitles dropped out at every edge while the full pass was backed
off or slower than a window lasts).
- Windows and full passes run on separate pools with separate in-flight caps, so a window never
queues behind (or is refused by) minute-long full passes — the pool comment promised that and
nothing enforced it.
- A pass that times out is TERMinated and keeps what it reached (published as partial) instead of
being killed and discarded.
- Lapsed failure memos are swept on every write (they were only pruned when the same key was read
again, so polling fresh keys grew the process without bound).
- `publish` no longer merges into a sidecar with no VTT behind it, or claims a region whose VTT write
failed, or overwrites an unreadable track with one window.
- A NUL in a rating_key names no row (it was a DataError, a 500, on every Plex route) and no longer
500s the status poll.
Tests: 16 new, each mutation-checked (18 mutations, all red on the test that names them).
- The <track>'s `error` never reached `onSubTrackError`: it does not bubble, and React 18 attaches no
listener of its own to a <track> (measured in Chrome and jsdom — `onError` 0 calls, `onErrorCapture`
1). Round 1's remount-and-give-up was dead code behind it. The hook now hands the player
`onErrorCapture`, and the test fires a real non-bubbling `error` at a rendered <track>.
- Once reachable, the retry burned its whole budget within milliseconds of an outage (a remount
fetches at once) and the give-up outlived turning subtitles off and on. Retries now wait (2 s,
doubling), running out is reported at once, and picking the track again starts a fresh budget.
- Until the first timeupdate the poll sent `sessionK` — still 0 while the session request was out,
and the PREVIOUS item's start after a move to the next episode. It now sends where the session was
asked to start, and the track choice belongs to the item it was made for, so the next item is not
asked about the old ordinal at the old position.
- A failing poll over a stale `partial` answer was silent: react-query keeps the last good data, the
track stayed "showable", and the notice only rendered for an unmounted track. The hook now decides
what the player says (`subNotice`), independently of whether a window is mounted.
Deep-review R2, plus one defect found while verifying it on localdev.
- The status poll re-armed every second after a FAILED request: `data` stays empty on an error,
so it read as "still preparing" for as long as the player was open — and the request was not
quiet, so a persistent 500 re-opened the global error dialog every second. It now backs off to
10 s (a blip still heals on its own) and is quiet; the player already shows the failure inline.
- A <track> whose own VTT fetch failed never fetched again: with the server's answer unchanged its
key was unchanged, so React kept the dead element — silently blank subtitles. The key (now built
in the hook, where it is tested) carries a failed-load count; after two remounts the track is
reported as unavailable instead.
- Found in UAT: until the first timeupdate `abs` is 0, so after a resume every poll said at=0 and
the first window was cut around the head of the film (a resume at 20:00 polled at=0 for as long
as it stayed paused). The poll reports the session's start until playback ticks. And the window's
dedup identity is the track plus a window-length bucket of its start — keyed on the track alone
(R1), the right window queued behind that wrong one.
The poll's start/stop rules finally have tests (every earlier one resolved a single fixed answer).
Verified on localdev against Westworld S1E6 resumed at 20:00: the polls carried at=1197, one
subtitle line on screen at 21:02, the poll stopped at `ready`; the real file's window (56 cues) +
full pass (608) merged to 608 — the old merge would have served 664. 11 mutations, all red.
Bug hunt 2026-09, items 8 and 12 — the two things the Plex player was measurably
lying about.
Item 8: picking a subtitle track showed nothing for a long time, and the reported
workaround was to stop/start until it suddenly worked. Measured on prod against a
17.06 GB MKV with two embedded SubRip tracks:
full pass, one track 154 s
full pass, both tracks in ONE run 111 s
-c:s copy (no WebVTT conversion) 143 s
from 1:00:00 to the end of file 66 s
a 630 s window at 1:00:00, both 8 s
So the conversion was never the cost: ffmpeg streams every byte of the container
between its seek point and its stop point, and the array delivers ~140 MB/s. The
only lever is reading less. Three changes follow from that:
* a window around the playhead is extracted and published FIRST (seconds), and
the full pass completes behind it;
* every embedded text track rides that same single read — picking Hungarian used
to cost a full pass and then switching to English cost another one;
* none of it happens inside a request any more. The endpoint answers 202 while a
background worker extracts, the player polls /status (carrying its position, so
the window follows the viewer), and one ffmpeg run finally has a timeout.
-copyts is deliberately absent from a windowed pass: with it ffmpeg ignores -t and
reads the whole container anyway (measured — a [0, 600 s] window still took the
full 145 s), so a window comes back on a zero-based clock and is shifted to
absolute time here. Cached tracks written by older builds have no coverage sidecar
and count as complete, so nothing is re-extracted after the upgrade.
The <track> is no longer mounted before the server has something to put in it; a
"Preparing subtitles: …" notice stands in, and a track that can never be shown says
why instead of leaving the viewer to conclude the picker does nothing.
Item 12: "Bitrate" read a constant 211 kbps on every remux, because it was the
master playlist's BANDWIDTH — which ffmpeg derives from the one stream whose rate
it knows, the -b:a 192k AAC track, plus 10%. It is a measurement now: bytes per
second of MEDIA from hls.js FRAG_LOADED, accumulated per fragment type and summed
(a multi-audio session's video and audio renditions cover the same media seconds,
so pooling them would report half the truth), and an honest dash until the first
fragment lands. The panel also finally names the audio and subtitle track in play.
Verified in the browser against the real Plex library, and every new test
mutation-checked.
The Plex player had a shortcuts overlay nobody else did, so the YouTube
player's Space/F/arrows and the Plex browser's Backspace were documented
nowhere. ui/KeyboardHelp is that sheet for every surface, opened by a
global `h` - not the conventional `?`, which is a Shift chord on a
Hungarian layout, while `h` is the key this app's reader already has in
their fingers from the player.
It renders the shared table filtered to the scopes that are LIVE: a
surface registers its scope with useKeyScope while mounted, and only
while its keys really do something - PlexBrowse deactivates its own
scope inside the player, where its Backspace no-ops, so the sheet cannot
promise a "Back one level" the handler declines to perform. Same rule
for the `when` rows: ⇧←/⇧→ are listed only inside a series, an answer
the player publishes because the sheet cannot ask.
No new overlay primitive, after checking: Modal already portals into
document.fullscreenElement ?? document.body (so this works over a
fullscreen player), registers an Escape layer, traps focus and handles
browser Back. Third time this epic that the thing was already built.
Shift+F10 is in the table as `handledLocally` - documented and sharing
the chord parser, but matched by useContextMenu on the focused row.
dispatch neither routes it nor demands a handler for it, so the
exhaustiveness check stays honest about what it actually covers.
Also: A/S have cycled the Plex audio and subtitle tracks since E5, but
silently - the only way to see where you landed was to open the tracks
menu, the exact round-trip the shortcut exists to avoid. cycleAudio and
cycleSubtitle now return the track they moved to, and the player flashes
it over the video.
Make Plex the source of truth for watch state:
- Write-back during playback: item_progress now pushes the resume position to
Plex on the periodic checkpoint too (not only the final flush), throttled to
one push per item every ~10s (in-memory, single-process rate limiter). The FE
now also fires an immediate (debounced) push on seek.
- Faster incremental pull: 30 → 15 min (plex_watch_sync_interval_min).
- Plex-authoritative pull: _pull_apply resolves a genuine divergence to Plex's
state instead of last-write-wins; the _same_state + synced_to_plex short-circuit
still prevents a freshly-pushed row from bouncing. Removed the now-unused
_LWW_TOLERANCE_S / _sift_ts.
Tests: 5 new in test_plex_watch_sync.py (Plex-wins resume/watched, no-bounce,
throttle final vs periodic).
E5 S6 frontend half.
Language threading (?lang=hu serves the HU overlay; en is the default):
- api/plex.ts: `lang` on plexLibrary / plexFacets / plexItem / plexShow (only
sent for hu, so EN URLs stay byte-stable); PlexItemDetail gains `rating`.
- queryKeys: plexItem / plexShow take an optional trailing lang so a switch caches
HU/EN separately; the ...rest keys (library/facets) already carry it. Prefix
invalidations (qk.plexShow(id) / qk.plexItem(id)) still match either.
- i18n: plexLang() collapses the UI language to en|hu for non-component code.
- PlexBrowse / PlexSidebar: thread lang into the grid, facets, item and show
queries (useTranslation re-renders on switch → the key changes → refetch).
- plexPlayerHooks: the optimistic resume setQueryData now keys by plexLang() so
it still lands on the language-keyed detail query.
- Clear the genre-filter selection on a language switch — genre chips are
language-specific strings, so a stale one silently empties the grid.
IMDb-only rating badge (folded-in S5b review #5):
- PlexInfo.tsx shows the IMDb badge + imdb.com link only when imdb_rating is
present; otherwise it renders the Plex audience `rating` (no IMDb link/branding),
so a non-IMDb score is never mislabelled. ratingMin filter keys off whichever
score is shown.
Tests: i18n parity.test.ts (en/hu key sets identical per namespace — currently
green, no drift). FE gate green: tsc / knip / lint clean, 213 vitest tests pass.
- applyVolume/setVol now pass the element's CURRENT level as the normalize
fallback instead of undefined, so a corrupt persisted volume holds the
playing level rather than jumping to PLEX_SCALE.default=1 (full) — the "full
blast" failure mode playerVolume.ts's header explicitly warns against. (The
old bare clamp muted instead; both are wrong for corrupt data.) readMerged
shallow-merges stored prefs without per-field validation, so a corrupt
volume is reachable.
- setVol normalises the level ONCE and both applies + persists that same value,
so the <video> element and the stored pref can never disagree.
- Test documents the hold-last-known contract (corrupt raw + valid fallback ->
fallback; only an unusable fallback lands on the scale default).
Gate green (tsc / eslint-0 / prettier / knip / vitest 83 / pytest 234).
Volume-consolidation (conservative — no behaviour or prefs-format change):
- playerVolume.ts is now scale-generic (a VolumeScale parameterises range /
default / integer rounding). YT_SCALE (0-100 ints) and PLEX_SCALE (0..1
float) bind the same tested core; the YouTube wrappers keep the original API
so the existing tests are unchanged.
- The Plex usePlayerVolume hook drops its bespoke clamp01 arithmetic for the
shared normalizeVolumeIn / stepVolumeIn at PLEX_SCALE. Side effect (a latent
bug fix): a corrupt persisted volume now falls back to the default instead of
a bare clamp silently muting it. The separate .muted flag stays Plex-only.
- clamp01 stays for the seek-bar fraction (its non-volume use).
- Tests: the generic core is covered at both scales (float no-round, corrupt ->
default, step/clamp) — the Plex-side arithmetic finally has unit coverage.
PlexPlayerSettings extraction (verbatim JSX move, behaviour-equivalent):
- The ~240-line gear/tuning panel (sync / playback / subtitle / clock tabs)
moves out of PlexPlayer into PlexPlayerSettings.tsx (a pure prefs+patchPrefs
view owning no state). PlexPlayer shrinks 1402 -> 1173 lines; Slider/Toggle
imports it no longer uses are dropped.
Gate green (tsc / eslint-0 / prettier / knip / vitest 83 / pytest 234). Dev
server smoke: app builds + loads clean, no console errors. The interactive
settings panel needs a playing Plex video (unreachable on localdev) -> owed to
the user's UAT.
S4a-4a of the PlexPlayer decomposition. Move audio/subtitle track
selection + subtitle rendering into usePlexTracks: the selected-ordinal
state, change/cycle audio+subtitle, the debounced sub-offset, the audio
A/V-sync offset, and the two subtitle effects (force-showing the mounted
track + positioning cues at the user's subPos). The shared media refs
(video/hls/audio/aoff/abs/multiAudio) stay component-owned and are passed
in, since loadSession + the detail effect write audioRef too; absRef is
hoisted above the hook call for that. No behaviour change; verified by
self-E2E (subtitle on/off via 'S' mounts/removes the <track>, mode
'showing', VTT 804 cues all positioned to line=subPos, subLang persists;
playback uninterrupted). Audio switch is single-track here so cycleAudio
correctly no-ops.
S4a-3b of the PlexPlayer decomposition. Move the intro/credits auto-skip
machinery (activeMarker detection, the skipProgress countdown, doSkip,
cancelAutoSkip + the running-interval and reset-on-id effects) into
useAutoSkip. The hook returns skipProgressRef / cancelAutoSkipRef — the
forward-declaration bridge the earlier keyboard/back handlers read to
cancel a running countdown; those two stable refs are now listed in the
backIntent/keyboard dep arrays (they were provably-stable local refs
before, params now). No behaviour change; verified by self-E2E (credits
marker detected -> countdown fill renders + advances while playing ->
auto-skip fires -> item marked Watched + player closes).
S4a-3a of the PlexPlayer decomposition. Move two byte-equivalent
behaviours into lib/plexPlayerHooks.ts: usePlexProgress (the 10s
interval flush + pause/pagehide beacon + reopen cache-patch checkpoint;
absRef stays in the component since seek/skip/ended mutate it too) and
usePlayerVolume (HTML5 <video> 0..1 volume + independent mute, persisted
+ re-applied per session). usePlayerVolume is the seam the later R12
volume-consolidation sprint will rework to share playerVolume.ts's
tested pure core with the YouTube player. No behaviour change; verified
by self-E2E (volume-bar sets + persists video.volume, 'm' toggles mute
keeping the level, pause fires plexProgress 200).
S4a-2 of the PlexPlayer decomposition. Move three self-contained,
byte-equivalent behaviours into lib/plexPlayerHooks.ts: useWallClock
(15s top-bar clock), useFullscreen (wrapper fs toggle + reactive flag),
and useControlsVisibility (auto-hiding control bar + wake). The ref
mirrors the hooks read (barAutoHide/menuOpen/video-paused) stay in the
component and are passed in, so the timer sees fresh state. No behaviour
change; verified by self-E2E (real HLS playback: clock renders, controls
auto-hide after 3s while playing, wake restores + stays while paused).
peter