systemctl cat nonexistent@ fails with assertion error

[nbraud]

systemd version the issue has been seen with

$ systemd --version                                                        :(
systemd 244 (244.1-2)
+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=hybrid

Used distribution
Debian 11 (testing, “bullseye”)

Expected behaviour you didn't see

$ systemctl cat notexist@
No files found for notexist@.service.

Unexpected behaviour you saw

$ systemctl cat notexist@
Assertion 'name' failed at src/shared/dropin.c:143, function unit_file_find_dirs(). Aborting.
[1]    63986 abort      systemctl cat notexist@

Steps to reproduce the problem
See above

Notes
The issue seems to be limited to non-existent, templated units:

• non-existent, non-templated units work fine;

$ systemctl cat notexist
No files found for notexist.service.

• exiting, templated units work.

$ systemctl cat hostapd@
# /lib/systemd/system/hostapd@.service
[...]

This was initially reported as Debian bug #950489.

[yuwata]

I cannot reproduce this with the current git master (and v243).

$ systemctl cat hoge@
No files found for hoge@.service.

Could you test with the current git master?

[yuwata]

Ah, this is already fixed by 7a670b1.

[yuwata]

@keszybz Could you backport the commit to the stable repository?

[mbiebl]

Thanks @yuwata . I've cherry-picked the fix in Debian for the time being.