Update: testparm will display this issue when /etc/samba/smb.conf is explicitly passed as an argument. Since testparm will pull configs from that location by default without explicit paths, we can use a workaround where we rely on the implicit location instead.

Proposed changes for kali-tweaks/helpers/samba lines 43 and 45 are as follows:
Remove the $SAMBA_CONFIG variable
#######################################################################
Line 43: https://gitlab.com/kalilinux/packages/kali-tweaks/-/blob/kali/master/helpers/samba#L43

• if ! testparm $SAMBA_CONFIG --suppress-prompt >/dev/null 2>&1; then
• if ! testparm --suppress-prompt >/dev/null 2>&1; then
  #######################################################################
  Line 45: https://gitlab.com/kalilinux/packages/kali-tweaks/-/blob/kali/master/helpers/samba#L45
• testparm $SAMBA_CONFIG --suppress-prompt
• testparm --suppress-prompt
  #######################################################################

Thanks for reporting! The variables SAMBA_CONFIG is needed for unit tests, where we don't use the default location /etc/samba/smb.conf. So we can't remove it.

The bug is really new. I tested and couldn't reproduce it. Then I upgraded the system:

<pre>
The following packages will be upgraded:
blueman catfish dirmngr ethtool firefox-esr fonts-urw-base35 gdisk gir1.2-nm-1.0 gnupg gnupg-l10n gnupg-utils gpg
gpg-agent gpg-wks-client gpg-wks-server gpgconf gpgsm gpgv gsfonts gstreamer1.0-plugins-good keyboard-configuration
libde265-0 libedit2 libfaad2 libflite1 libfuse2 libglu1-mesa libigdgmm12 libmfx1 libmysofa1 libnm0 libopenmpt0 libpopt0
libsndfile1 libsoup-3.0-0 libsoup-3.0-common libspeechd2 libtheora0 man-db network-manager opensc opensc-pkcs11
pinentry-curses pinentry-gnome3 python-apt-common python3-apt python3-speechd python3-webencodings runit-helper
speech-dispatcher speech-dispatcher-audio-plugins speech-dispatcher-espeak-ng xbitmaps
</pre>

And then I could reproduce the bug. At first glance, it's not easy to see what package is guilty... However:

<pre>
┌──(kali㉿kali)-[~]
└─$ ldd /usr/bin/testparm | grep libpopt
libpopt.so.0 => /lib/x86_64-linux-gnu/libpopt.so.0 (0x00007f9b8aa87000)

┌──(kali㉿kali)-[~]
└─$ apt show libpopt0
[...]
Description: lib for parsing cmdline parameters
[...]
</pre>

Surely that's where the regression comes from. I opened an issue on the Debian bugtracker: https://bugs.debian.org/1022826

Thank you so much, arnaudr!

Yeah, I thought the workaround was a long shot, but now I'm really curios as to how you got to the point of locating the exact package/library that caused this. Only if you have the time to share your thought process though!

I've never submitted any bug reports outside of here tbh, so it's a bit of a learning curve for me. I really appreciate you doing this <3 Many thanks!

how you got to the point of locating the exact package/library that caused this

I was just lucky :) I picked up a one week-old Kali VM, the bugs didn't manifest, I upgraded it, and the bug was there. So the bug was introduced by one of the packages that were pulled in by the upgrade (list above). Then I just had to find which package was related to testparm.

"testparm" is provided by samba-common-bin (you can see that with "apt-file search bin/testparm"), then I looked at the dependencies for samba-common-bin (with "apt show samba-common-bin"), compared that with the packages that were upgraded. libpopt0 was the only one that I spot. I could confirm that testparm links against libpopt with "ldd /usr/bin/testparm | grep libpopt". Plus, libpopt is a library to parse cmdline arguments, and that's exactly the problem that we have here, testparm chokes if we pass it a config file in argument.

But if I didn't have a (rather short) list of packages that were brought in by the "apt full-upgrade" command, it would have been much harder to find out.

Anyway, so a new version of Samba was uploaded to Debian unstable, it should be in Kali at some point next week.

Ideally, kali-tweaks should handle this kind of unexpected errors more gracefully, and a setting that is not functional should just be greyed out, or something like that. I opened an issue for that: https://gitlab.com/kalilinux/packages/kali-tweaks/-/issues/36

And finally, I just released kali-tweaks 2022.4.1 with the workaround that you mentioned (ie. not giving a config file to testparm). Should land in Kali rolling in a day or so, I'll keep an eye on it.

Thanks again for the detailed report!

Awesome! That's exactly what I was looking for!
Thank you so much for taking the time to share your thought process, arnaudr :)

kali-tweaks has been one of my favorite tools for quickly managing configs, so many thanks for such a great solution!