mark_write_pending's window was a fixed few seconds, started before the
PUT and the confirming /device/0 refresh that follows it -- but that
refresh is a full summary poll, which can legitimately take far longer
than that on these AC devices. The window routinely expired while the
confirm poll was still in flight, so a stale read (the device's own
resource tree hadn't caught up to the instant physical change yet)
landed unprotected and reverted the optimistic write, with nothing to
correct it again until the next scheduled summary poll. That's the
20-60s lag both issues report even after the earlier optimistic-apply
fix.
Size the window to cover the PUT and confirm-poll timeouts combined,
and release it as soon as that round trip actually completes (success
or failure) instead of leaving it open for the rest of a now much
longer window.
Marc Billow
615c5d5aa9