mercurial/scmposix.py

crecord: fix issue when backgrounding editor would leave artefact

Before this patch:
- if a user was entering a commit message after having ran the curses
interface
- and then uses ctrl-z, followed by fg to put the editor in the
background/foreground
- then the curses interface would leave artefact on the screen of
the editor, making entering the commit message a difficult task

This happened because ncurses registers a signal handler for SIGTSTP and
does not restore the original signal handler after running.
More info at:
http://stackoverflow.com/questions/31440392/
curses-wrapper-messing-up-terminal-after-background-foreground-sequence/
31441709#31441709

This patch restores the original value of the signal handler after
running the curses interface and therefore fixes this issue.
It don't know how to add a test for this issue, I tested the scenario
above manually and it works correctly with the patch.

import sys, os
import osutil

def _rcfiles(path):
    rcs = [os.path.join(path, 'hgrc')]
    rcdir = os.path.join(path, 'hgrc.d')
    try:
        rcs.extend([os.path.join(rcdir, f)
                    for f, kind in osutil.listdir(rcdir)
                    if f.endswith(".rc")])
    except OSError:
        pass
    return rcs

def systemrcpath():
    path = []
    if sys.platform == 'plan9':
        root = 'lib/mercurial'
    else:
        root = 'etc/mercurial'
    # old mod_python does not set sys.argv
    if len(getattr(sys, 'argv', [])) > 0:
        p = os.path.dirname(os.path.dirname(sys.argv[0]))
        if p != '/':
            path.extend(_rcfiles(os.path.join(p, root)))
    path.extend(_rcfiles('/' + root))
    return path

def userrcpath():
    if sys.platform == 'plan9':
        return [os.environ['home'] + '/lib/hgrc']
    else:
        return [os.path.expanduser('~/.hgrc')]