contrib/showstack.py

rebase: preserve working copy when redoing in-mem rebase on disk

When in-memory rebase runs into conflicts, we retry it on disk. But
before we do that, we abort the in-memory rebase. That is done because
even though it's mostly in memory, there are still a few state files
written (e.g. the merge state). We should make it not write those
files so we don't need to abort, but for the stable branch, let's
explicitly clear the state we need to clear instead of running the
usual abort code.

Differential Revision: https://phab.mercurial-scm.org/D5356

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

from __future__ import absolute_import, print_function
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 sigexit(*args):
    sigshow(*args)
    print('alarm!')
    sys.exit(1)

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