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

prepush: add more precise error messages

Part of the patch is from [e-mail]

- indicate the branch name where there are multiple heads
- give better advice when hitting a possible race, where new heads are added
  between discovery and the call to branchmap(). In that case, asking the user
  to merge isn't helpful, since only remote has the changes.

import os, sys
from mercurial import hg, ui

TESTDIR = os.environ["TESTDIR"]

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

# this is what symlink would do on a non-symlink file system
def symlink_failure(src, dst):
    raise OSError, (1, "Operation not permitted")
os.symlink = symlink_failure

# now try cloning a repo which contains symlinks
u = ui.ui()
hg.clone(u, os.path.join(TESTDIR, 'test-no-symlinks.hg'), 'test1')