view hgext/graphlog.py @ 44207:e960c30d7e50

rust-cpython: mark all PyLeaked methods as unsafe

Unfortunately, these methods can be abused to obtain the inner 'static
reference. The simplest (pseudo-code) example is:

  let leaked: PyLeaked<&'static _> = shared.leak_immutable();
  let static_ref: &'static _ = &*leaked.try_borrow(py)?;
      // PyLeakedRef::deref() tries to bound the lifetime to itself, but
      // the underlying data is a &'static reference, so the returned
      // reference can be &'static.

This problem can be easily fixed by coercing the lifetime, but there are
many other ways to achieve that, and there wouldn't be a generic solution:

  let leaked: PyLeaked<&'static [_]> = shared.leak_immutable();
  let leaked_iter: PyLeaked<slice::Iter<'static, _>>
      = unsafe { leaked.map(|v| v.iter()) };
  let static_slice: &'static [_] = leaked_iter.try_borrow(py)?.as_slice();

So basically I failed to design the safe borrowing interface. Maybe we'll
instead have to add much more restricted interface on top of the unsafe
PyLeaked methods? For instance, Iterator::next() could be implemented if
its Item type is not &'a (where 'a may be cheated.)

Anyway, this seems not an easy issue, so it's probably better to leave the
current interface as unsafe, and get broader comments while upstreaming this
feature.

# ASCII graph log extension for Mercurial
#
# Copyright 2007 Joel Rosdahl <[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.

'''command to view revision graphs from a shell (DEPRECATED)

The functionality of this extension has been include in core Mercurial
since version 2.3. Please use :hg:`log -G ...` instead.

This extension adds a --graph option to the incoming, outgoing and log
commands. When this options is given, an ASCII representation of the
revision graph is also shown.
'''

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    cmdutil,
    commands,
    registrar,
)

cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'


@command(
    b'glog',
    [
        (
            b'f',
            b'follow',
            None,
            _(
                b'follow changeset history, or file history across copies and renames'
            ),
        ),
        (
            b'',
            b'follow-first',
            None,
            _(b'only follow the first parent of merge changesets (DEPRECATED)'),
        ),
        (
            b'd',
            b'date',
            b'',
            _(b'show revisions matching date spec'),
            _(b'DATE'),
        ),
        (b'C', b'copies', None, _(b'show copied files')),
        (
            b'k',
            b'keyword',
            [],
            _(b'do case-insensitive search for a given text'),
            _(b'TEXT'),
        ),
        (
            b'r',
            b'rev',
            [],
            _(b'show the specified revision or revset'),
            _(b'REV'),
        ),
        (
            b'',
            b'removed',
            None,
            _(b'include revisions where files were removed'),
        ),
        (b'm', b'only-merges', None, _(b'show only merges (DEPRECATED)')),
        (b'u', b'user', [], _(b'revisions committed by user'), _(b'USER')),
        (
            b'',
            b'only-branch',
            [],
            _(
                b'show only changesets within the given named branch (DEPRECATED)'
            ),
            _(b'BRANCH'),
        ),
        (
            b'b',
            b'branch',
            [],
            _(b'show changesets within the given named branch'),
            _(b'BRANCH'),
        ),
        (
            b'P',
            b'prune',
            [],
            _(b'do not display revision or any of its ancestors'),
            _(b'REV'),
        ),
    ]
    + cmdutil.logopts
    + cmdutil.walkopts,
    _(b'[OPTION]... [FILE]'),
    helpcategory=command.CATEGORY_CHANGE_NAVIGATION,
    inferrepo=True,
)
def glog(ui, repo, *pats, **opts):
    """show revision history alongside an ASCII revision graph

    Print a revision history alongside a revision graph drawn with
    ASCII characters.

    Nodes printed as an @ character are parents of the working
    directory.

    This is an alias to :hg:`log -G`.
    """
    opts['graph'] = True
    return commands.log(ui, repo, *pats, **opts)