contrib/showstack.py

revpair: do not optimize tree to check for odd-range spec

At cc3a30ff9490, we had to optimize a parsed tree to resolve x^:y ambiguity.
Since we've moved the resolution of x^:y to parse(), we no longer have to call
optimize(). Therefore, (x:y) can be taken as a single expression, not an odd
range expression x:y.

# 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