hg

shelve: rewrite check for unknown shelf to delete

The code would try to delete the shelf's .patch file and if that
raised an exception, it would convert it to an `error.Abort`. This
patch rewrites it so the check is done upfront. I find it easier to
read that way. It's now clear enough that I removed the comment
explaining it as well.

As Joerg pointed out during review, another differences is that the
old code would move a `.hg` file without its `.patch` friend to backup
before it realized that the `.patch` file was missing. The new code
will error out earlier and not move the `.hg` file, which seems like
an improvement. That should only matter on corrupt `.hg/shelved/`
directories, however.

Differential Revision: https://phab.mercurial-scm.org/D9697

#!/usr/bin/env python3
#
# mercurial - scalable distributed SCM
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# 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 os
import sys

libdir = '@LIBDIR@'

if libdir != '@' 'LIBDIR' '@':
    if not os.path.isabs(libdir):
        libdir = os.path.join(
            os.path.dirname(os.path.realpath(__file__)), libdir
        )
        libdir = os.path.abspath(libdir)
    sys.path.insert(0, libdir)

# Make `pip install --user ...` packages available to the official Windows
# build.  Most py2 packaging installs directly into the system python
# environment, so no changes are necessary for other platforms.  The Windows
# py2 package uses py2exe, which lacks a `site` module.  Hardcode it according
# to the documentation.
if getattr(sys, 'frozen', None) == 'console_exe':
    vi = sys.version_info
    sys.path.append(
        os.path.join(
            os.environ['APPDATA'],
            'Python',
            'Python%d%d' % (vi[0], vi[1]),
            'site-packages',
        )
    )

from hgdemandimport import tracing

with tracing.log('hg script'):
    # enable importing on demand to reduce startup time
    try:
        if sys.version_info[0] < 3 or sys.version_info >= (3, 6):
            import hgdemandimport

            hgdemandimport.enable()
    except ImportError:
        sys.stderr.write(
            "abort: couldn't find mercurial libraries in [%s]\n"
            % ' '.join(sys.path)
        )
        sys.stderr.write("(check your install and PYTHONPATH)\n")
        sys.exit(-1)

    from mercurial import dispatch

    dispatch.run()