async_send_command's settle guard used DEFAULT_SETTLE_S's fixed few
seconds, which is long enough for fields that update instantly on the
device but not for ones that visibly take a few seconds of internal
validation or hardware movement to catch up. Issue #9's washer packs
cycle/detergent/softener selection into /course/vs/0's shared options[]
array, and that settling time regularly outlasted the fixed window --
same device, same integration, but /washer/vs/0's temperature/spin
fields (plain flags) confirmed instantly while these didn't. The short
window expired before the confirm poll (or the device itself) caught
up, so a stale read landed unprotected and reverted the optimistic
value, only to self-correct again once a later poll saw the real
change -- reading to the user as the write reverting and then
reapplying itself a few seconds later.
Size the window to always outlast the PUT and the confirming refresh's
poll combined, as issues #17/#53 also needed, but without that fix's
early-release mechanism (reverted previously for its own races around
overlapping writes) -- just hold the guard for the full window and let
it expire on its own.
Marc Billow
020402c82f