absorb: preserve changesets which were already empty
Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.
This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.
#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]