Subject: 29.0.50; url-retrieve-synchronously with timeout causes process-query-on-exit

From: Phil Sainty <[email-masked]>
Date: Sat, 01 Oct 2022 23:55:05 +1300

If you use the TIMEOUT argument to `url-retrieve-synchronously' and the
response is not obtained within that duration, then the process created
for that request causes query-on-exit behaviour.  I can reproduce this
in all the Emacs builds I have, including this 29.0.50 build.

;; With a short timeout causing the request to be aborted:

(url-retrieve-synchronously "http://www.example.com" nil nil 0.01)
nil

M-x list-processes
www.example.com -- open -- -- Main (network connection to 
www.example.com:80)

C-x C-c
Active processes exist; kill them and exit anyway? (yes or no)

;; With a long timeout (or a nil timeout):

(url-retrieve-synchronously "http://www.example.com" nil nil 5)
#<buffer  *http www.example.com:80*>

M-x list-processes
www.example.com -- open -- -- Main (network connection to 
www.example.com:80)

C-x C-c
exits without any process-related prompt

I'm not sure why the network connection remains open in either case, but
regardless of that it seems as if process-query-on-exit-flag is set if
the request times out, and cleared if it does not.  The query-on-exit
case seems to me like a bug, especially when there is no obvious way to
obtain the process object and change the flag.

I found bug #34607 when searching, but I don't understand what's being
discussed there; especially the example code for this:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34607#22
which seems to me like it would be signalling an error when it winds
up evaluating (with-current-buffer nil ...)

-Phil

In GNU Emacs 29.0.50 (build 4, x86_64-pc-linux-gnu, X toolkit, cairo 
version 1.15.10, Xaw scroll bars)
  of 2022-07-15 built on phil-lp
Repository revision: 00eb894a56d63fad3573a53dd57c323289711512
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 
11.0.12008000
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