bug#21729: doc-view messed up by early auto-revert

[Tassilo Horn <tsdh@gnu.org>]

Nicolas Richard <youngfrog@members.fsf.org> writes:

> Tassilo Horn <tsdh@gnu.org> writes:
>> I think in doc-view-mode it's obvious enough when a file is being
>> reverted, so maybe we should set auto-revert-verbose to nil
>> buffer-locally?
>
> Sometimes emacs does weird things, and I think it's nice if it
> explains what it does, even if it should be obvious.  Morever the
> message is not only useful while the file is being reverted, but also
> after the fact.  e.g. if I have foo.pdf open, and that file is
> controlled by owncloud and gets updated by the cloud, I like to find
> this information in *Messages*.

Yes, I see.  But then we could still set `auto-revert-verbose' to nil
buffer-locally and issue that message in `doc-view-revert-buffer'.  The
problem with the message from autorevert.el is that it'll be displayed
even though doc-view decides that it cannot auto-revert right now
because the file is corrupted/not ready yet.

Alternatively, we could of course enhance autorevert.el, e.g., by
introducing some buffer-local variable `auto-revert-predicate' which is
run by auto-revert in order to test if the current buffer can be
reverted right now.  That could then be used by doc-view, and I guess
there are other modes which could make use of such a feature, too.

Stefan, do you think that would be a good idea?

Bye,
Tassilo