contrib/showstack.py

setup: configure py2exe config via environment variables

The Inno Setup and WiX installers ship a different set of packages
with py2exe builds. And there are multiple WiX installer variants
(e.g. TortoiseHG).

Since there are multiple variants of py2exe configs and they
can be defined by entities not in our repository, let's
provide a mechanism for setup.py to supplement behavior via
environment variables. This is slighly less hacky than a setup.cfg
file IMO since the caller doesn't need to worry about mutating
global state of the source directory.

Differential Revision: https://phab.mercurial-scm.org/D6092

# 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