ui: add special-purpose atexit functionality
In spite of its longstanding use, Python's built-in atexit code is
not suitable for Mercurial's purposes, for several reasons:
* Handlers run after application code has finished.
* Because of this, the code that runs handlers swallows exceptions
(since there's no possible stacktrace to associate errors with).
If we're lucky, we'll get something spat out to stderr (if stderr
still works), which of course isn't any use in a big deployment
where it's important that exceptions get logged and aggregated.
* Mercurial's current atexit handlers make unfortunate assumptions
about process state (specifically stdio) that, coupled with the
above problems, make it impossible to deal with certain categories
of error (try "hg status > /dev/full" on a Linux box).
* In Python 3, the atexit implementation is completely hidden, so
we can't hijack the platform's atexit code to run handlers at a
time of our choosing.
As a result, here's a perfectly cromulent atexit-like implementation
over which we have control. This lets us decide exactly when the
handlers run (after each request has completed), and control what
the process state is when that occurs (and afterwards).
# 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 __future__ import absolute_import
from mercurial.i18n import _
from mercurial.node import (
short,
)
from mercurial import (
cmdutil,
commands,
error,
exchange,
hg,
lock,
util,
)
release = lock.release
cmdtable = {}
command = cmdutil.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 = 'ships-with-hg-core'
@command('fetch',
[('r', 'rev', [],
_('a specific revision you would like to pull'), _('REV')),
('e', 'edit', None, _('invoke editor on commit messages')),
('', 'force-editor', None, _('edit commit message (DEPRECATED)')),
('', 'switch-parent', None, _('switch parents when merging')),
] + commands.commitopts + commands.commitopts2 + commands.remoteopts,
_('hg fetch [SOURCE]'))
def fetch(ui, repo, source='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.
'''
date = opts.get('date')
if date:
opts['date'] = util.parsedate(date)
parent, _p2 = repo.dirstate.parents()
branch = repo.dirstate.branch()
try:
branchnode = repo.branchtip(branch)
except error.RepoLookupError:
branchnode = None
if parent != branchnode:
raise error.Abort(_('working directory not at branch tip'),
hint=_("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(_('multiple heads in this branch '
'(use "hg heads ." and "hg merge" to merge)'))
other = hg.peer(repo, opts, ui.expandpath(source))
ui.status(_('pulling from %s\n') %
util.hidepassword(ui.expandpath(source)))
revs = None
if opts['rev']:
try:
revs = [other.lookup(rev) for rev in opts['rev']]
except error.CapabilityError:
err = _("other repository doesn't support revision lookup, "
"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(_('not merging with %d other new branch heads '
'(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['switch_parent']:
firstparent, secondparent = newparent, newheads[0]
else:
firstparent, secondparent = newheads[0], newparent
ui.status(_('updating to %d:%s\n') %
(repo.changelog.rev(firstparent),
short(firstparent)))
hg.clean(repo, firstparent)
ui.status(_('merging with %d:%s\n') %
(repo.changelog.rev(secondparent), short(secondparent)))
err = hg.merge(repo, secondparent, remind=False)
if not err:
# we don't translate commit messages
message = (cmdutil.logmessage(ui, opts) or
('Automated merge with %s' %
util.removeauth(other.url())))
editopt = opts.get('edit') or opts.get('force_editor')
editor = cmdutil.getcommiteditor(edit=editopt, editform='fetch')
n = repo.commit(message, opts['user'], opts['date'], editor=editor)
ui.status(_('new changeset %d:%s merges remote changes '
'with local\n') % (repo.changelog.rev(n),
short(n)))
return err
finally:
release(lock, wlock)