view hgext/record.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

# record.py
#
# Copyright 2007 Bryan O'Sullivan <[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.

'''commands to interactively select changes for commit/qrefresh (DEPRECATED)

The feature provided by this extension has been moved into core Mercurial as
:hg:`commit --interactive`.'''

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    cmdutil,
    commands,
    error,
    extensions,
    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"record",
    # same options as commit + white space diff options
    [c for c in commands.table[b'commit|ci'][1][:] if c[1] != b"interactive"]
    + cmdutil.diffwsopts,
    _(b'hg record [OPTION]... [FILE]...'),
    helpcategory=command.CATEGORY_COMMITTING,
)
def record(ui, repo, *pats, **opts):
    """interactively select changes to commit

    If a list of files is omitted, all changes reported by :hg:`status`
    will be candidates for recording.

    See :hg:`help dates` for a list of formats valid for -d/--date.

    If using the text interface (see :hg:`help config`),
    you will be prompted for whether to record changes to each
    modified file, and for files with multiple changes, for each
    change to use. For each query, the following responses are
    possible::

      y - record this change
      n - skip this change
      e - edit this change manually

      s - skip remaining changes to this file
      f - record remaining changes to this file

      d - done, skip remaining changes and files
      a - record all changes to all remaining files
      q - quit, recording no changes

      ? - display help

    This command is not available when committing a merge."""

    if not ui.interactive():
        raise error.Abort(
            _(b'running non-interactively, use %s instead') % b'commit'
        )

    opts["interactive"] = True
    overrides = {(b'experimental', b'crecord'): False}
    with ui.configoverride(overrides, b'record'):
        return commands.commit(ui, repo, *pats, **opts)


def qrefresh(origfn, ui, repo, *pats, **opts):
    if not opts['interactive']:
        return origfn(ui, repo, *pats, **opts)

    mq = extensions.find(b'mq')

    def committomq(ui, repo, *pats, **opts):
        # At this point the working copy contains only changes that
        # were accepted. All other changes were reverted.
        # We can't pass *pats here since qrefresh will undo all other
        # changed files in the patch that aren't in pats.
        mq.refresh(ui, repo, **opts)

    # backup all changed files
    cmdutil.dorecord(
        ui, repo, committomq, None, True, cmdutil.recordfilter, *pats, **opts
    )


# This command registration is replaced during uisetup().
@command(
    b'qrecord',
    [],
    _(b'hg qrecord [OPTION]... PATCH [FILE]...'),
    helpcategory=command.CATEGORY_COMMITTING,
    inferrepo=True,
)
def qrecord(ui, repo, patch, *pats, **opts):
    """interactively record a new patch

    See :hg:`help qnew` & :hg:`help record` for more information and
    usage.
    """
    return _qrecord(b'qnew', ui, repo, patch, *pats, **opts)


def _qrecord(cmdsuggest, ui, repo, patch, *pats, **opts):
    try:
        mq = extensions.find(b'mq')
    except KeyError:
        raise error.Abort(_(b"'mq' extension not loaded"))

    repo.mq.checkpatchname(patch)

    def committomq(ui, repo, *pats, **opts):
        opts['checkname'] = False
        mq.new(ui, repo, patch, *pats, **opts)

    overrides = {(b'experimental', b'crecord'): False}
    with ui.configoverride(overrides, b'record'):
        cmdutil.checkunfinished(repo)
        cmdutil.dorecord(
            ui,
            repo,
            committomq,
            cmdsuggest,
            False,
            cmdutil.recordfilter,
            *pats,
            **opts
        )


def qnew(origfn, ui, repo, patch, *args, **opts):
    if opts['interactive']:
        return _qrecord(None, ui, repo, patch, *args, **opts)
    return origfn(ui, repo, patch, *args, **opts)


def uisetup(ui):
    try:
        mq = extensions.find(b'mq')
    except KeyError:
        return

    cmdtable[b"qrecord"] = (
        qrecord,
        # same options as qnew, but copy them so we don't get
        # -i/--interactive for qrecord and add white space diff options
        mq.cmdtable[b'qnew'][1][:] + cmdutil.diffwsopts,
        _(b'hg qrecord [OPTION]... PATCH [FILE]...'),
    )

    _wrapcmd(b'qnew', mq.cmdtable, qnew, _(b"interactively record a new patch"))
    _wrapcmd(
        b'qrefresh',
        mq.cmdtable,
        qrefresh,
        _(b"interactively select changes to refresh"),
    )


def _wrapcmd(cmd, table, wrapfn, msg):
    entry = extensions.wrapcommand(table, cmd, wrapfn)
    entry[1].append((b'i', b'interactive', None, msg))