The composer status stack polls `process.list` every 5s while a background
process row is on screen. `process.list` is session-scoped, so against a
runtime id the gateway no longer holds it returns 4001 "session not found".
`refreshBackgroundProcesses` swallowed *every* failure with a bare `catch {}`
commented "transient socket loss". A gone session is not transient: the poll
re-sent the same dead runtime id every 5 seconds for the lifetime of the
window. On one machine this produced 31,518 gateway rejections in a day
(vs 663 the day before), 18,614 of them against a single runtime id, and it
is what users see reported as "sessions stopped with a session not found
error" after an update.
The trigger is a reconnect, not the poll itself: anything that mints a fresh
runtime (gateway restart, the #94219 reconnect/replay work, an idle-reaped
pooled backend) strands the id the status stack is still holding, and nothing
in this path ever re-checked it.
Distinguish the two failure classes:
- 4001 / "session not found" is TERMINAL for that runtime id — latch the id
and stop polling it.
- A timeout or transport error is transient — keep retrying, since the
session may well still be alive. Misclassifying that direction would
silently freeze the status stack on a healthy session.
The latch is cleared when the status stack (re)binds a session id, so a
session that comes back under a fresh runtime resumes polling normally
rather than staying dark for the life of the app.
Also name the method in the gateway's 4001 warning. That line was added in
c305839442 "for diagnosability", but without the RPC name it cannot say WHICH
client call is looping — the reason this storm could not be attributed from
the logs alone. A ContextVar set in `handle_request` carries it; it is
diagnostic only and never used for authorization.
Tests:
- composer-status: 4001 stops the poll, a timeout does not, one gone session
never suppresses a healthy sibling, and a rebind resumes polling.
- tui_gateway: the rejection warning names the method.
Justin Johnson
c19849cd02