annotate contrib/showstack.py @ 31499:31d2ddfd338c

color: sync text attributes and buffered text output on Windows (issue5508)

I originally noticed that log output wasn't being colored after 3a4c0905f357,
but there were other complications too.  With a bunch of untracked files, only
the first 1K of characters were colored pink, and the rest were normal white.  A
single modified file at the top would also be colored pink.

Line buffering and full buffering are treated as the same thing in Windows [1],
meaning the stream is either buffered or not.  I can't find any explicit
documentation to say stdout is unbuffered by default when attached to a console
(but some internet postings indicated that is the case[2]).  Therefore, it seems
that explicit flushes are better than just not reopening stdout.

NB: pager is now on by default, and needs to be disabled to see any color on
Windows.

[1] https://msdn.microsoft.com/en-us/library/86cebhfs(v=vs.140).aspx
[2] https://sourceforge.net/p/mingw/mailman/message/27121137/

# 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