Bug#999637: systemd: systemctl help foo.service doesn't work with file:/path/to/README.md

[Nicholas D Steeves]

Package: systemd
Version: 249.6-1
Severity: normal

Hi,

Apologies for not reporting from a sid system.  It affects systemd in
buster and bullseye as well, but I'm not sure if the version of
systemd in those version is new enough to support this type of
documentation.  Steps to reproduce:

1. Install a testing system, including the standard system tools task
2. Upgrade to sid
3. Run "systemctl help foo" for a service file that uses the following
under the [Unit] section:

  Documentation="file:/usr/share/doc/foo/README.md"
4. Result: STDERR "Can't show: file:/usr/share/doc/foo/README.md".
Return code of 0!?  That's a separate bug, I think.

This is of course also the case with the README.md.gz that are almost
always used on Debian systems.  I tested the uncompressed case in case
systemctl didn't have the ability to read compressed file.

I'm not sure where this functionality is broken.  Could it be that
it's not enabled in the build?  Could it be systemd needs to call a
pager, but our systemd hasn't been configured to use
/etc/alternatives/pager?  This is all speculation, but my suspicion is
that it's actually upstream bug.

Regards,
Nicholas