tests/test-symlink-os-yes-fs-no.py

merge: add `--abort` flag which can abort the merge

Currently we don't have a good functionality to abort the merge and tell user to
do `hg update -C .` which can leads to different results if user missed the '.'
and moreover does not align with other abort functionalities like rebase, shelve
etc.

This patch adds `hg merge --abort` which will abort the ongoing merge and take
us back to the chagneset where we started from. Works in both cases when merge
resulted in conflicts and when there were no conflicts.

.. feature::

    A `--abort` flag to merge command to abort the ongoing merge.

Differential Revision: https://phab.mercurial-scm.org/D1829

from __future__ import absolute_import

import os
import sys
import time
from mercurial import (
    commands,
    hg,
    ui as uimod,
    util,
)

TESTDIR = os.environ["TESTDIR"]
BUNDLEPATH = os.path.join(TESTDIR, 'bundles', 'test-no-symlinks.hg')

# only makes sense to test on os which supports symlinks
if not getattr(os, "symlink", False):
    sys.exit(80) # SKIPPED_STATUS defined in run-tests.py

u = uimod.ui.load()
# hide outer repo
hg.peer(u, {}, '.', create=True)

# clone with symlink support
hg.clone(u, {}, BUNDLEPATH, 'test0')

repo = hg.repository(u, 'test0')

# wait a bit, or the status call wont update the dirstate
time.sleep(1)
commands.status(u, repo)

# now disable symlink support -- this is what os.symlink would do on a
# non-symlink file system
def symlink_failure(src, dst):
    raise OSError(1, "Operation not permitted")
os.symlink = symlink_failure
def islink_failure(path):
    return False
os.path.islink = islink_failure

# dereference links as if a Samba server has exported this to a
# Windows client
for f in 'test0/a.lnk', 'test0/d/b.lnk':
    os.unlink(f)
    fp = open(f, 'wb')
    fp.write(util.readfile(f[:-4]))
    fp.close()

# reload repository
u = uimod.ui.load()
repo = hg.repository(u, 'test0')
commands.status(u, repo)

# try cloning a repo which contains symlinks
u = uimod.ui.load()
hg.clone(u, {}, BUNDLEPATH, 'test1')