"make lisp/eshell/esh-proc-tests" fails intermittently since 7e50861ca7ed3f620fe62ac6572f6e88b3600ece

[Jens Schmidt <jschmidt4gnu@vodafonemail.de>]

Not sure whether anybody has seen or reported already:  Approx. 1 of 5
executions of "make lisp/eshell/esh-proc-tests" fail for me like this:

------------------------- snip -------------------------
make[1]: Entering directory '/home/jschmidt/work/emacs-master/test'
  GEN      lisp/eshell/esh-proc-tests.log
Running 23 tests (2023-09-24 20:32:11+0200, selector `(not (tag :unstable))')
Loading em-alias...
Loading em-banner...
Loading em-basic...
Loading em-cmpl...
Loading em-extpipe...
Loading em-glob...
Loading em-hist...
Loading em-ls...
Loading em-pred...
Loading em-prompt...
Loading em-script...
Loading em-term...
Loading em-unix...
   passed   1/23  esh-proc-test/exit-status/failure (0.117111 sec)
   passed   2/23  esh-proc-test/exit-status/success (0.105469 sec)
   passed   3/23  esh-proc-test/exit-status/with-stderr-pipe (0.105925 sec)
   passed   4/23  esh-proc-test/kill-pipeline (0.108324 sec)
   passed   5/23  esh-proc-test/kill-pipeline-head (0.108148 sec)
   passed   6/23  esh-proc-test/kill-process/background-prompt (0.005315 sec)
[sleep]+ Done (/usr/bin/sleep 100)
   passed   7/23  esh-proc-test/kill-process/foreground-only (0.207743 sec)
   passed   8/23  esh-proc-test/kill-process/redirect-message (0.004864 sec)
Tramp: Sending command `exec sh -i'
Tramp: Found remote shell prompt on `sappc2'
Tramp: Sending command `exec sh -i'
Tramp: Found remote shell prompt on `sappc2'
   passed   9/23  esh-proc-test/output/remote-redirect (0.157058 sec)
   passed  10/23  esh-proc-test/output/stderr-to-buffer (0.106075 sec)
   passed  11/23  esh-proc-test/output/stdout-and-stderr-to-buffer (0.105911 sec)
   passed  12/23  esh-proc-test/output/stdout-to-buffer (0.105907 sec)
   passed  13/23  esh-proc-test/output/to-screen (0.105792 sec)
   passed  14/23  esh-proc-test/pipeline-connection-type/first (0.055700 sec)
   passed  15/23  esh-proc-test/pipeline-connection-type/last (0.056159 sec)
make[1]: *** [Makefile:181: lisp/eshell/esh-proc-tests.log] Broken pipe
make[1]: Leaving directory '/home/jschmidt/work/emacs-master/test'
make: *** [Makefile:247: lisp/eshell/esh-proc-tests] Error 2
------------------------- snip -------------------------

I bisected with

------------------------- snip -------------------------
#!/bin/bash

make FAST=true -j8 bootstrap || exit 1
for (( i = 0; i < 30; i++ )); do
  ( cd test && make lisp/eshell/esh-proc-tests ) || exit 1
done

exit 0
------------------------- snip -------------------------

to

------------------------- snip -------------------------
7e50861ca7ed3f620fe62ac6572f6e88b3600ece is the first bad commit
commit 7e50861ca7ed3f620fe62ac6572f6e88b3600ece
Author: Jim Porter <jporterbugs@gmail.com>
Date:   Thu Sep 14 17:51:16 2023 -0700

    ; Simplify how to use 'eshell-debug-command'

    Now, 'eshell-debug-command' works more like 'format-message', which is
    how we usually use it.

    * lisp/eshell/esh-util.el (eshell-always-debug-command): New function.
    (eshell-debug-command): Simplify.  Update callers.

 lisp/eshell/esh-arg.el  |  6 +++---
 lisp/eshell/esh-cmd.el  | 10 ++++++----
 lisp/eshell/esh-proc.el | 41 +++++++++++++++++------------------------
 lisp/eshell/esh-util.el | 26 +++++++++++++++++---------
 4 files changed, 43 insertions(+), 40 deletions(-)
bisect run success
------------------------- snip -------------------------

Pls let me know whether I should open a separate bug for this.