view contrib/showstack.py @ 44768:9d441f820c8b stable

automation: support building Windows wheels for Python 3.7 and 3.8

The time has come to support Python 3 on Windows.

Let's teach our automation code to produce Windows wheels for
Python 3.7 and 3.8.

We could theoretically support 3.5 and 3.6. But I don't think
it is worth it. People on Windows generally use the Mercurial
installers, not wheels. And I'd prefer we limit variability
and not have to worry about supporting earlier Python versions
if it can be helped.

As part of this, we change the invocation of pip to `python.exe -m pip`,
as this is what is being recommended in Python docs these days. And
it seemed to be required to avoid a weird build error. Why, I'm not
sure. But it looks like pip was having trouble finding a Visual Studio
files when invoked as `pip.exe` but not when using `python.exe -m pip`.
Who knows.

Differential Revision: https://phab.mercurial-scm.org/D8478

# 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