contrib/showstack.py

morestatus: check whether the conflict message is None before printing

There are cases like bisect when the conflict message can be None. So we make
sure that we don't print None in that case.

Thanks to Martin for catching this.

Differential Revision: https://phab.mercurial-scm.org/D461

# showstack.py - extension to dump a Python stack trace on signal
#
# binds to both SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)

from __future__ import absolute_import
import signal
import sys
import traceback

def sigshow(*args):
    sys.stderr.write("\n")
    traceback.print_stack(args[1], limit=10, file=sys.stderr)
    sys.stderr.write("----\n")

def extsetup(ui):
    signal.signal(signal.SIGQUIT, sigshow)
    try:
        signal.signal(signal.SIGINFO, sigshow)
    except AttributeError:
        pass