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

sshpeer: allow for additional environment passing to ssh exe

We already have the ability to customize the ssh command line arguments, let's
add the ability to customize its environment as well.

Example use-case is ssh.exe from Git on Windows. If `HOME` enviroment variable
is present and has some non-empty value, ssh.exe will try to access that
location for some stuff (for example, it seems for resolving `~` in
`.ssh/config`). Git for Windows seems to sometimess set this variable to the
value of `/home/username` which probably works under Git Bash, but does not
work in a native `cmd.exe` or `powershell`. Whatever the root cause, setting
`HOME` to be an empty string heals things. Therefore, some distributors
might want to set `sshenv.HOME=` in the configuration (seems less intrusive
that forcing everyone to tweak their env).

Test Plan:
- rt

Differential Revision: https://phab.mercurial-scm.org/D1683

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')