tests/test-nointerrupt.t

nodemap: write nodemap data on disk

Let us start writing data on disk (so that we can read it from there later).
This series of changeset is going to focus first on having data on disk and
updating it.

Right now the data is written right next to the revlog data, in the store. We
might move it to cache (with proper cache validation mechanism) later, but for
now revlog have a storevfs instance and it is simpler to us it. The right
location for this data is not the focus of this series.

Differential Revision: https://phab.mercurial-scm.org/D7835

#require no-windows

Dummy extension simulating unsafe long running command
  $ cat > sleepext.py <<EOF
  > import itertools
  > import time
  > 
  > from mercurial.i18n import _
  > from mercurial import registrar
  > 
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > 
  > @command(b'sleep', [], _(b'TIME'), norepo=True)
  > def sleep(ui, sleeptime=b"1", **opts):
  >     with ui.uninterruptible():
  >         for _i in itertools.repeat(None, int(sleeptime)):
  >             time.sleep(1)
  >         ui.warn(b"end of unsafe operation\n")
  >     ui.warn(b"%s second(s) passed\n" % sleeptime)
  > EOF

Kludge to emulate timeout(1) which is not generally available.
  $ cat > timeout.py <<EOF
  > from __future__ import print_function
  > import argparse
  > import signal
  > import subprocess
  > import sys
  > import time
  > 
  > ap = argparse.ArgumentParser()
  > ap.add_argument('-s', nargs=1, default='SIGTERM')
  > ap.add_argument('duration', nargs=1, type=int)
  > ap.add_argument('argv', nargs='*')
  > opts = ap.parse_args()
  > try:
  >     sig = int(opts.s[0])
  > except ValueError:
  >     sname = opts.s[0]
  >     if not sname.startswith('SIG'):
  >         sname = 'SIG' + sname
  >     sig = getattr(signal, sname)
  > proc = subprocess.Popen(opts.argv)
  > time.sleep(opts.duration[0])
  > proc.poll()
  > if proc.returncode is None:
  >     proc.send_signal(sig)
  >     proc.wait()
  >     sys.exit(124)
  > EOF

Set up repository
  $ hg init repo
  $ cd repo
  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > sleepext = ../sleepext.py
  > EOF

Test ctrl-c
  $ python $TESTTMP/timeout.py -s INT 1 hg sleep 2
  interrupted!
  [124]

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > nointerrupt = yes
  > EOF

  $ python $TESTTMP/timeout.py -s INT 1 hg sleep 2
  interrupted!
  [124]

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > nointerrupt-interactiveonly = False
  > EOF

  $ python $TESTTMP/timeout.py -s INT 1 hg sleep 2
  shutting down cleanly
  press ^C again to terminate immediately (dangerous)
  end of unsafe operation
  interrupted!
  [124]