Notification warning count inconsistency

[grke]

Reported on the mailing list, burp 2.2.18

When I try to restore the backup into a temporary directory
/media/backup/snapshot by the command:
"burp -c /etc/burp/ubuntu.conf -a r -d /media/backup/snapshot",
everything works fine except for an unknown warning returned by burp with exit
code 2.

The notification email subject is "restore succeeded: ubuntu (1 warnings)" but the counters in the log message say 0 warnings.

In the server-side log:

burp[27654]: doing restore confirmed
burp[27655]: Logging to /backup/data/ubuntu/0000037 2020-04-16 20:06:10
+0200/restorelog
burp[27654]: WARNING: /media/backup/snapshot: Is not in a subdir of
'/media/backup/snapshot'
burp[27655]: Compressing /backup/data/ubuntu/0000037 2020-04-16
20:06:10 +0200/restorelog to /backup/data/ubuntu/0000037 2020-04-16 20:06:10
+0200/restorelog.gz...
burp[27655]: WARNING: /media/backup/snapshot: Is not in a subdir of
'/media/backup/snapshot'
burp[27654]: restore finished

[grke]

It looks to me like maybe the canonicalisation check gets confused when dealing with the final directory, when specifying an identical destination directory.

And also, there may be some kind of race condition where a very late warning gets logged server-side after the server-side client-specific log gets closed.