Re: Re: Insight into the mystery hangs

["Pedro A. Aranda" <paaguti@gmail.com>]

Hi,


very interesting thread. It has helped me with my "mistery hang" too ;-)

Eli writes.

>> Date: Mon, 12 Feb 2024 13:26:16 -0500
>> From: "Eric S. Raymond"<esr@thyrsus.com>
>> Cc:emacs-devel@gnu.org
>>
>> Eli Zaretskii<eliz@gnu.org>:
>>> Isn't that call issued from the mode-line display?  If so, that is
>>> done from redisplay, and redisplay cannot enter debugger, so it
>>> catches all errors.  If you want to produce Lisp backtraces from Lisp
>>> code called by redisplay, you need to use the facilities documented in
>>> the node "Debugging Redisplay" in the ELisp Reference manual.
>> 1. Thinking about it, I can see why redisplay can't be allowed to enter
>> the debugger. Infinite regress...
>>
>> 2. I don't know if that subprocess is called from the modeline
>> code. Probably, but I'd have to dig into vc.el to check. I won't have
>> time for that for a few days yet.
>>
>> 3. Assuming that it is called from the modeline code, the question
>> shifts from "Why did I have so much trouble generating a debug trace?"
>> to "How could I get one at all"?" There's some kind of timing issue,
>> I think.
> If you eventually can get Emacs into producing a backtrace, the
> facilities described in the node "Debugging Redisplay", mentioned
> above, should allow you to have it saved in a special buffer that you
> can then examine.

The main problem I have is how much time you have to invest until you 
get that 'eventual' backtrace. Say time and read expertise, etc. An 
'average user', if such person exists, should be able to get the basic 
information for the development team to move forward and "kill the bug".

Having said that, I was using variable `vc-mode' in my mode-line. And 
when I resized emacs while editing any file (under VC or not) it would 
hang. Removing that and not experiencing further hangs have been one and 
the same thing.


Just my .02 cents,/PA