Subject: bug#10195: 24.0.92; M-w may no longer provide visual feedback

From: Michael Welsh Duggan <[email-masked]>
Date: Sat, 03 Dec 2011 12:38:12 -0500

Eli Zaretskii <[email-masked]> writes:

>> From: Michael Welsh Duggan <[email-masked]>
>> Cc: [email-masked],  [email-masked]
>> Date: Sat, 03 Dec 2011 10:19:06 -0500
>> 
>> I just tried this again in a random buffer in my running non -Q emacs.
>> The first M-w caused the cursor to bounce, the second did not, the third
>> did, the fourth and fifth did not.  This is why I called the behavior
>> inconsistent.  I just tried it in emacs -Q again, and had it bounce
>> three times out of 15 tries.
>
> Does "C-h l" show all the 15 M-w keystrokes you did?
>
>> I am running in an unoptimized debug build with assertions turned on,
>> and am familiar with gdb.  If there is any way I can help debug this,
>> please let me know.

Yes, and the region does end up in the kill ring.

> M-w calls sit-for after bouncing point to the position of mark; the
> default waiting period is 1 sec.  How about instrumenting sit-for with
> calls to `message' and seeing what's going on there?  One possibility
> is that some input event terminates the wait immediately (see
> sit-for's code).  Another possibility is that something happens in
> read-event, in which case you will need to use GDB.  But I think it
> would be good to see what's going on in sit-for before you go to the C
> level.
>
> Another idea is to replace the call to sit-for in kill-ring-save with
> a call to sleep-for, and see if that changes anything.  If it does,
> the probably culprit is sit-for and whatever it calls.

I'm away from home until late tonight.  I'll give this (or something
similar) a try then.

-- 
Michael Welsh Duggan
([email-masked])