[Python-buildbots] Buildbot won't restart if blank pidfile exists

Just came across a weird problem. Not sure if it's something to raise here or elsewhere.

My buildslave got aborted due to a host reboot, but after resetting everything, I was unable to run "buildslave restart" as I normally did. It crashed out with 'invalid literal for int() with base 10' trying to parse an empty string as "pid = int(f.read().strip())". (Can't copy and paste from the VM, sorry - full traceback would be quite tedious.) Attempting "buildslave start" timed out after ten seconds, probably for the same reason (I didn't actually check though). Turns out that having an empty twistd.pid file prevents restart; removing this file made everything work perfectly. Seemed very odd.

ChrisA