hg status subprocess occasionally has returncode == 0 in non-mercurial checkouts

[rpatterson]

Intermittently and rarely the mercurial repository check subprocess reports a successful returncode of 0 in a non-mercurial checkout.

I confirmed this by running:

self.process.popen('hg status', echo=False, echo2=False)

...repeatedly and found that 1 out of every 10-20 returned (0, []). I confirmed that this doesn't seem to be a problem with the actual hg status command by running:

while [1] ; do hg status && echo XXX ; done

...which never printed XXX.

So maybe there's a rare bug in the subprocess handling?

[stefanholek]

Hm, you on Python 2? On Mac?

Maybe this fix applied for 3.2+ compatibility broke lesser Pythons: 0f0a9c3

Mercurial is a very "slow" subprocess compared to the pure C git and svn, and poll() from bg thread has stopped working in 3.2...

Could you perhaps revert that commit in your env and try to reproduce the errors? Thanks!