A KDE user observed that if you 'dock' a GTK PuTTY window to the side
of the screen (by dragging it to the RH edge, causing it to
half-maximise over the right-hand half of the display, similarly to
Windows), and then send a terminal resize sequence, then PuTTY fails
the assertion in term_resize_request_completed() which expects that an
unacknowledged resize request was currently in flight.
When drawing_area_setup() calls term_resize_request_completed() in
response to the inst->term_resize_notification_required flag, it
resets the inst->win_resize_pending flag, but doesn't reset
inst->term_resize_notification_required. As a result, the _next_ call
to drawing_area_setup will find that flag still set, and make a
duplicate call to term_resize_request_completed, after the terminal no
longer believes it's waiting for a response to a resize request. And
in this 'docked to the right-hand side of the display' state, KDE
apparently triggers two calls to drawing_area_setup() in quick
succession, making this bug manifest.
I could fix this by clearing inst->term_resize_notification_required.
But inspecting all the other call sites, it seems clear to me that my
original intention was for inst->term_resize_notification_required to
be a flag that's only meaningful if inst->win_resize_pending is set.
So I think a better fix is to conditionalise the check in
drawing_area_setup so that we don't even check
inst->term_resize_notification_required if !inst->win_resize_pending.
(cherry picked from commit fec6719a2b)
65639fbbe7