Fox 2026-06-06: "closed firefox on both phones [they] are both still
in the list" — listener-roster entries persisting indefinitely after
mobile Firefox close.
Two facts collided:
1. SERVER (proxy.unturf.com main.go aliveJanitorTick ~line 1872):
listeners are fully exempt from the heartbeat-stall reaper.
Justified fox 2026-06-04 because the page's {type:"alive"}
timer throttles hard on backgrounded mobile tabs (1Hz on
Android, paused on iOS power-save) — without the exemption,
mobile listeners lost their seat every time they tab-switched.
2. CLIENT (this file, sendByeIfRealClose): pagehide with
event.persisted=true means the page is going into bfcache
(mobile app-switch / tab-close-to-bfcache / lock screen),
so we SKIPPED the 'bye' message to keep PCs warm for resume.
Justified fox 2026-06-03 because "the phone leaving and
coming back cannot hear the music" — bye-driven SFU eviction
killed the speaker's publish + subscribe PCs.
Net: a mobile Firefox close fires pagehide(persisted=true) →
no 'bye' → server has only readTimeout (120s) + hiccup grace
(8s) to detect the dead socket → ~128s of phantom listener
seat in every other client's roster.
The bfcache justification on the CLIENT side was always
specific to speakers (they have PCs to protect). LISTENERS:
- have no publisher PC
- finalizeLeave at main.go:1089 explicitly exempts them from
evictFromSFU (their subscriber PC stays alive through the
bye)
- re-handshake fresh on pageshow via POST /subscribe (same
path as a cold join)
So for listeners, sending 'bye' on persisted=true is
roster-only cleanup: peer-left broadcast, members.delete(uuid)
on every other client, brief disappearance from the room. On
pageshow they re-handshake and reappear — same UX as a cold
rejoin, which already works.
Fix: split the bfcache rule by role. Send 'bye' on pagehide
even when persisted=true if myRole === 'listener'. Speakers
keep the original bfcache skip exactly.
Server-side backstop (60s listener-specific TTL replacing the
full exemption) ships as a separate commit in proxy.unturf.com
so 'bye' losses (carrier NAT eating the TCP shutdown, abrupt
process kill, custom Firefox close paths) still get reaped
within the minute.
Pinned by test/sendbye-fsm.test.js — extracts
sendByeIfRealClose from this page and drives 9 scenarios
covering each (role, persisted) combination plus defensive
edges (no event, ws not open, post-demote listener state).
Wired into test-all via test-sendbye target.
Russell Ballestrini
5e8cdadb29