bug#26973: 26.0.50; sleep-for behavior changes with global-auto-revert-mode enabled

[Andreas Politz <politza@hochschule-trier.de>]

Eli Zaretskii <eliz@gnu.org> writes:

> Like I said: I've lost track of this discussion.  [...]

Activating global-auto-revert-mode seems to lead to starvation of the
collection of output from running processes in an inotify build.
Inhibiting the generation of open, close and access file-events seems to
have fixed this problem.

This lead to the hypotheses that, in case the above types of events are
reported, reading file-events while idling may by itself lead to the
generation of more file-events and thus making this process stuck in a
cycle.

Autorevert resp. filenotify.el does not include these events in its
event-mask passed to the various back-ends, such that this problem could
not be perceived, unless the back-ends are used directly.  (Except for
inotify, were a constant, promiscuous mask was previously used in order
to work around a different problem.)

So, if the above is true, other back-ends could exhibit the same
behavior, if they were to be instructed to generate open/close/access
events.  Again, since these events are not used by filenotify.el, it
would only show, if the back-end is invoked directly,
e.g. w32notify-add-watch with last-access-time.

-ap