[Buildbot-devel] buildbot SIGUSR2 during build

[Brian Warner]

> > process killed by signal 12
> > program finished with exit code -1

> Ignore this please, it seems these errors are caused by some of our library
> code not handling stdout/err redirection properly.

In case it helps anyone in the future, the other signal-related weirdness
I've noticed in a buildbot context was when a Twisted unit test that verified
signal-delivery stopped working. SIGHUP wasn't being delivered to the target
process, even though running the same test from the command line worked just
fine.

It turned out that I was running the buildslave under a 'nohup' environment
(I forget whether it was with a '&' in the shell command or with some other
daemonization scheme on top of the normal 'twistd' command). This
ignore-SIGHUP behavior was inherited by the buildslave process, and then by
the program-under-test ('trial', in this case). The test case that did a
kill(SIGHUP) failed because nohup somehow installed a signal handler, and the
test assumed that the signal handler was in its default (uncaught) state.

I think the fix was to have the test explicitly set up a SIG_DFL handler for
SIGHUP, or maybe just remove SIGHUP from the set of signals it was checking.

Anyway, just figured I'd throw a note about it in the list archives in case
anyone hits a similar problem again.

 -Brian