rust-hg-core: move from `ouroboros` to `self_cell`
`ouroboros` has a fundamental soundness problem that, while not applicable
today, could become applicable given new compiler optimizations.ยน
`self_cell` is a crate that accomplishes a lot of the same things that
`ouroboros` did while remaining sound (that is, unless a new soundness issue
is discovered) by not assuming as much about the memory layout of the program.
`self_cell` has been scrutinized heavily in the past few months by very
competent people, some from the compiler team and has shown no weaknesses
for a while, with a 1.0 stable release coming out a couple months ago.
Our internal API is exactly the same, this is just an implementation detail.
To reiterate, no actual soundness issue was found with our use of `ouroboros`,
but there might be evolutions of `rustc` (or even a future separate compiler)
that could generate unsound code.
[1] https://github.com/joshua-maros/ouroboros/issues/88
# fetch.py - pull and merge remote changes
#
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''pull, update and merge in one command (DEPRECATED)'''
from mercurial.i18n import _
from mercurial.node import short
from mercurial import (
cmdutil,
error,
exchange,
hg,
lock,
pycompat,
registrar,
)
from mercurial.utils import (
dateutil,
urlutil,
)
release = lock.release
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'fetch',
[
(
b'r',
b'rev',
[],
_(b'a specific revision you would like to pull'),
_(b'REV'),
),
(b'', b'edit', None, _(b'invoke editor on commit messages')),
(b'', b'force-editor', None, _(b'edit commit message (DEPRECATED)')),
(b'', b'switch-parent', None, _(b'switch parents when merging')),
]
+ cmdutil.commitopts
+ cmdutil.commitopts2
+ cmdutil.remoteopts,
_(b'hg fetch [SOURCE]'),
helpcategory=command.CATEGORY_REMOTE_REPO_MANAGEMENT,
)
def fetch(ui, repo, source=b'default', **opts):
"""pull changes from a remote repository, merge new changes if needed.
This finds all changes from the repository at the specified path
or URL and adds them to the local repository.
If the pulled changes add a new branch head, the head is
automatically merged, and the result of the merge is committed.
Otherwise, the working directory is updated to include the new
changes.
When a merge is needed, the working directory is first updated to
the newly pulled changes. Local changes are then merged into the
pulled changes. To switch the merge order, use --switch-parent.
See :hg:`help dates` for a list of formats valid for -d/--date.
Returns 0 on success.
"""
opts = pycompat.byteskwargs(opts)
date = opts.get(b'date')
if date:
opts[b'date'] = dateutil.parsedate(date)
parent = repo.dirstate.p1()
branch = repo.dirstate.branch()
try:
branchnode = repo.branchtip(branch)
except error.RepoLookupError:
branchnode = None
if parent != branchnode:
raise error.Abort(
_(b'working directory not at branch tip'),
hint=_(b"use 'hg update' to check out branch tip"),
)
wlock = lock = None
try:
wlock = repo.wlock()
lock = repo.lock()
cmdutil.bailifchanged(repo)
bheads = repo.branchheads(branch)
bheads = [head for head in bheads if len(repo[head].children()) == 0]
if len(bheads) > 1:
raise error.Abort(
_(
b'multiple heads in this branch '
b'(use "hg heads ." and "hg merge" to merge)'
)
)
path = urlutil.get_unique_pull_path_obj(b'fetch', ui, source)
other = hg.peer(repo, opts, path)
ui.status(_(b'pulling from %s\n') % urlutil.hidepassword(path.loc))
revs = None
if opts[b'rev']:
try:
revs = [other.lookup(rev) for rev in opts[b'rev']]
except error.CapabilityError:
err = _(
b"other repository doesn't support revision lookup, "
b"so a rev cannot be specified."
)
raise error.Abort(err)
# Are there any changes at all?
modheads = exchange.pull(repo, other, heads=revs).cgresult
if modheads == 0:
return 0
# Is this a simple fast-forward along the current branch?
newheads = repo.branchheads(branch)
newchildren = repo.changelog.nodesbetween([parent], newheads)[2]
if len(newheads) == 1 and len(newchildren):
if newchildren[0] != parent:
return hg.update(repo, newchildren[0])
else:
return 0
# Are there more than one additional branch heads?
newchildren = [n for n in newchildren if n != parent]
newparent = parent
if newchildren:
newparent = newchildren[0]
hg.clean(repo, newparent)
newheads = [n for n in newheads if n != newparent]
if len(newheads) > 1:
ui.status(
_(
b'not merging with %d other new branch heads '
b'(use "hg heads ." and "hg merge" to merge them)\n'
)
% (len(newheads) - 1)
)
return 1
if not newheads:
return 0
# Otherwise, let's merge.
err = False
if newheads:
# By default, we consider the repository we're pulling
# *from* as authoritative, so we merge our changes into
# theirs.
if opts[b'switch_parent']:
firstparent, secondparent = newparent, newheads[0]
else:
firstparent, secondparent = newheads[0], newparent
ui.status(
_(b'updating to %d:%s\n')
% (repo.changelog.rev(firstparent), short(firstparent))
)
hg.clean(repo, firstparent)
p2ctx = repo[secondparent]
ui.status(
_(b'merging with %d:%s\n') % (p2ctx.rev(), short(secondparent))
)
err = hg.merge(p2ctx, remind=False)
if not err:
# we don't translate commit messages
message = cmdutil.logmessage(ui, opts) or (
b'Automated merge with %s' % urlutil.removeauth(other.url())
)
editopt = opts.get(b'edit') or opts.get(b'force_editor')
editor = cmdutil.getcommiteditor(edit=editopt, editform=b'fetch')
n = repo.commit(
message, opts[b'user'], opts[b'date'], editor=editor
)
ui.status(
_(b'new changeset %d:%s merges remote changes with local\n')
% (repo.changelog.rev(n), short(n))
)
return err
finally:
release(lock, wlock)