Consider setting mtime to 1 instead of 0 to workaround logic bugs in other apps?

[srd424]

I've just been bitten by this bug in cron which causes it not to load any crontab entries if the mtime of /etc/crontab and /var/spool/crontab are both 0:

https://bugs.launchpad.net/ubuntu/+source/cron/+bug/1773229

It's the sort of logic bug which I can easily imagine existing in other software too - is it worth setting the mtime to 1 instead of 0, or is there a particular reason why 0 is important?

[srd424]

(For completeness, #1469 and links from there document the original decision to set all files to 0.)

[cgwalters]

I've just been bitten by this bug in cron which causes it not to load any crontab entries if the mtime of /etc/crontab and /var/spool/crontab are both 0:

Ah, ouch. You might consider using systemd timers instead FWIW.

is it worth setting the mtime to 1 instead of 0, or is there a particular reason why 0 is important?

We had to pick a value. I don't think we can really easily change it now.