contrib/showstack.py

tests: demonstrate that rename is followed to wrong parent from merge

This test case shows another way that copies are handled differently
between `hg st` (pathcopies()) and `hg co -m` (mergecopies). The
reason is that pathcopies() calls _tracefiles(), which checks that the
file nodeid of an ancestor matches the file nodeid in the base
commit. mergecopies() should probably be doing the same.

Differential Revision: https://phab.mercurial-scm.org/D6323

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