view mercurial/txnutil.py @ 49452:74fb1842f8b9

phase: rename the requirement for internal-phase (BC)

The previous requirements covers both `internal` and `archived` phase.  However,
the `archived` phase is not ready for usage (while the internal one is mostly
ready for years). So we split the archived on in a dedicated requirements (see
previous changeset for details) and rename the one for internal-phase. This will
avoid older client trying to use the archived phase on `internal` only
repositories.

Since the requirements stayed experimental since its introduction. It seems
fine to drop the previous version.

# 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 . import encoding


def mayhavepending(root):
    """return whether 'root' may have pending changes, which are
    visible to this process.
    """
    return root == encoding.environ.get(b'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(b'%s.pending' % filename, **kwargs), True)
        except FileNotFoundError:
            pass
    return (vfs(filename, **kwargs), False)