SysVInit services targets parsing broken

[Berbe]

Describe the bug

Since the rewrite of _service() to _comp_complete_service() in 2.12, SysVInit services targets are not being parsed correctly anymore.

This issue only occurs to me now, having upgraded from Devuan Daedalus 5 (deriving from Debian Bookworm 12) to Devuan Excalibur 6 (deriving from Debian Trixie 13).
The bash-completion package is untouched from upstream Debian.

To reproduce

1. Grab either:
   • a live ISO of Devuan Excalibur 6 from one of the mirrors
   • a live ISO of Debian Trixie 13 (for instance the XFCE one)
2. Start a shell
3. Type sudo service acpid
4. Press
5. Wrong output: sudo service acpid start stop restart reload force-reload status start stop
   

Expected behavior

1. Grab either:
   • a live ISO of Devuan Excalibur 6 from one of the mirrors
   • a live ISO of Debian Trixie 13 (for instance the XFCE one)
2. Start a shell
3. Type sudo service acpid
4. Press
5. Targets are being listed

Versions (please complete the following information)

• [*] Operating system name/distribution and version:
  • Devuan Excalibur 6
  • Debian Trixie 13
• [*] bash version, echo "$BASH_VERSION": 5.2.37(1)-release
• [*] bash-completion version, (IFS=.; echo "${BASH_COMPLETION_VERSINFO[*]}"): 2.16.0

Additional context

A patch for the 2.16.0 version would be nice, so it could be suggested as at update at Debian's

Investigation

I was able to produce a basic hack patch, taking the pre-2.12 working part and overwriting the since-2.12 failing one:

--- /usr/share/bash-completion/bash_completion    2025-11-04 20:38:46.147140782 +0100
+++ /usr/share/bash-completion/bash_completion.fixed     2025-11-04 20:38:59.323846976 +0100
@@ -2093,9 +2093,9 @@
     else
         local sysvdirs
         _comp_sysvdirs || return 1
-        _comp_compgen_split -l -- "$(command sed -e 'y/|/ /' \
-            -ne 's/^.*\(U\|msg_u\)sage.*{\(.*\)}.*$/\2/p' \
-            "${sysvdirs[0]}/${prev##*/}" 2>/dev/null) start stop"
+        COMPREPLY=($(compgen -W '`command sed -e "y/|/ /" \
+            -ne "s/^.*\(U\|msg_u\)sage.*{\(.*\)}.*$/\2/p" \
+            ${sysvdirs[0]}/${prev##*/} 2>/dev/null` start stop' -- "$cur"))
     fi
 } &&
     complete -F _comp_complete_service service

With this, services targets autocompletion works again, even though it is unsatisfactory to go back to the old behaviour and not use the refactored function.

[yedayak]

Can you show the output of the inner sed command there?
Something like this should work:

_comp_sysvdirs
command sed -e 'y/|/ /' \
            -ne 's/^.*\(U\|msg_u\)sage.*{\(.*\)}.*$/\2/p' \
            "${sysvdirs[0]}/${prev##*/}" 2>/dev/null

[Berbe]

The list of targets on a single line, just like the unparsed output being produced:

#!/bin/bash
service=/etc/init.d/acpid
. /usr/share/bash-completion/bash_completion
_comp_sysvdirs
command sed -e 'y/|/ /' \
            -ne 's/^.*\(U\|msg_u\)sage.*{\(.*\)}.*$/\2/p' \
            "${service}" 2>/dev/null

start stop restart reload force-reload status

[yedayak]

If you remove the -l from the _comp_compgen_split invocation, does it fix the issue for you?

[Berbe]

It seems to do the trick, yeah!

From what I understand from _comp_compgen_split() definition, this -l option seems to change IFS from \t\n to merely \n, hence not splitting a space-separated list as returned by the previously tested call: am I correct?

[yedayak]

Yeah you're correct. Do you want to make a PR with the fix? Also if you could give me an example service file I will try to make a test for _comp_complete_service

[Berbe]

I am attaching the /etc/init.d/acpid file as provided by the acpid_2.0.34-1+b1_amd64.deb package taken from https://packages.debian.org/trixie/acpid:
acpid.txt

As a maintainer, you should be able to edit my PR to add the test to it through a dedicated commit: thanks!