view hgext/graphlog.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

# 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)