mercurial/txnutil.py

tests: support passing testcase after .t paths that have path separators

This probably could have been implemented by changing the regex above this bit
of code, but I wasn't sure if it would end up handling various OSes correctly,
so I decided to go with this version instead.

Previously:

    $ tests/run-tests.py tests/test-ssh.t -l
    running 2 tests using 2 parallel processes
    ..
    # Ran 2 tests, 0 skipped, 0 failed.

    $ tests/run-tests.py tests/test-ssh.t#sshv1 -l
    running 0 tests using 0 parallel processes

    # Ran 0 tests, 0 skipped, 0 failed.

Now:

    $ tests/run-tests.py tests/test-ssh.t -l
    running 2 tests using 2 parallel processes
    ..
    # Ran 2 tests, 0 skipped, 0 failed.

    $ tests/run-tests.py tests/test-ssh.t#sshv1 -l
    running 1 tests using 1 parallel processes
    .
    # Ran 1 tests, 0 skipped, 0 failed.

Differential Revision: https://phab.mercurial-scm.org/D5535

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno

from . import (
    encoding,
)

def mayhavepending(root):
    '''return whether 'root' may have pending changes, which are
    visible to this process.
    '''
    return root == encoding.environ.get('HG_PENDING')

def trypending(root, vfs, filename, **kwargs):
    '''Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    '''
    if mayhavepending(root):
        try:
            return (vfs('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)