bug#57930: 27.2; error in process sentinel

[Eli Zaretskii]

> From: Raoul Comninos <revrari@mweb.co.za>
> Date: Mon, 19 Sep 2022 12:38:59 +0200
> 
> 
> Doing a find-name search in dired frequently renders this error:
> 
> error in process sentinel: Wrong type argument: integer-or-marker-p, nil
> 
> For example. If I want to see if there are any JPG files in my videos
> folder. I invoke C-x d, then find-name-dired. Then the error occurs. I
> tried this in Emacs 27 and 28.

I tried reproducing this, but couldn't.  I guess your case has some
hidden aspects.  So:

  . does this happen in "emacs -Q"?
  . if it does happen in "emacs -Q", please set debug-on-error to a
    non-nil value, run the command to get a backtrace, and post the
    backtrace here
  . if it doesn't happen in "emacs -Q", please try to find the
    customization that causes this

The bug report seems to indicate that the problem happens in the
process-sentinel:

  error in process sentinel: Wrong type argument: integer-or-marker-p, nil [2 
times]

but it doesn't give enough details to investigate further.