bookflow: new extension for bookmark-based branching
This extension should be helpful for feature branches - based workflows.
At my company we first considered branches, but weren't sure about creating a lot of permanent objects.
We tried bookmarks, but found some scenarios to be difficult to control.
The main problem, was the active bookmark being moved on update.
Disabling that made everything a lot more predictable.
Bookmarks move on commit, and updating means switching between them.
The extension also implements a few minor features to better guide the workflow:
- hg bookmark NAME can be ambiguous (create or move), unlike hg branch. The extension requires -rev to move.
- require an active bookmark on commit.
- some bookmarks can be protected (like @), useful for teams, that require code reviews.
- block creation of new branches.
The initial implementation requires no changes in the core, but it does rely on some implementation details.
I thought it may be useful to discuss the functionality first, and then focus making the code more robust.
Differential Revision: https://phab.mercurial-scm.org/D4312
# Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''share a common history between several working directories
Automatic Pooled Storage for Clones
-----------------------------------
When this extension is active, :hg:`clone` can be configured to
automatically share/pool storage across multiple clones. This
mode effectively converts :hg:`clone` to :hg:`clone` + :hg:`share`.
The benefit of using this mode is the automatic management of
store paths and intelligent pooling of related repositories.
The following ``share.`` config options influence this feature:
``share.pool``
Filesystem path where shared repository data will be stored. When
defined, :hg:`clone` will automatically use shared repository
storage instead of creating a store inside each clone.
``share.poolnaming``
How directory names in ``share.pool`` are constructed.
"identity" means the name is derived from the first changeset in the
repository. In this mode, different remotes share storage if their
root/initial changeset is identical. In this mode, the local shared
repository is an aggregate of all encountered remote repositories.
"remote" means the name is derived from the source repository's
path or URL. In this mode, storage is only shared if the path or URL
requested in the :hg:`clone` command matches exactly to a repository
that was cloned before.
The default naming mode is "identity".
'''
from __future__ import absolute_import
import errno
from mercurial.i18n import _
from mercurial import (
bookmarks,
commands,
error,
extensions,
hg,
registrar,
txnutil,
util,
)
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 = 'ships-with-hg-core'
@command('share',
[('U', 'noupdate', None, _('do not create a working directory')),
('B', 'bookmarks', None, _('also share bookmarks')),
('', 'relative', None, _('point to source using a relative path '
'(EXPERIMENTAL)')),
],
_('[-U] [-B] SOURCE [DEST]'),
helpcategory=command.CATEGORY_REPO_CREATION,
norepo=True)
def share(ui, source, dest=None, noupdate=False, bookmarks=False,
relative=False):
"""create a new shared repository
Initialize a new repository and working directory that shares its
history (and optionally bookmarks) with another repository.
.. note::
using rollback or extensions that destroy/modify history (mq,
rebase, etc.) can cause considerable confusion with shared
clones. In particular, if two shared clones are both updated to
the same changeset, and one of them destroys that changeset
with rollback, the other clone will suddenly stop working: all
operations will fail with "abort: working directory has unknown
parent". The only known workaround is to use debugsetparents on
the broken clone to reset it to a changeset that still exists.
"""
hg.share(ui, source, dest=dest, update=not noupdate,
bookmarks=bookmarks, relative=relative)
return 0
@command('unshare', [], '', helpcategory=command.CATEGORY_MAINTENANCE)
def unshare(ui, repo):
"""convert a shared repository to a normal one
Copy the store data to the repo and remove the sharedpath data.
"""
if not repo.shared():
raise error.Abort(_("this is not a shared repo"))
hg.unshare(ui, repo)
# Wrap clone command to pass auto share options.
def clone(orig, ui, source, *args, **opts):
pool = ui.config('share', 'pool')
if pool:
pool = util.expandpath(pool)
opts[r'shareopts'] = {
'pool': pool,
'mode': ui.config('share', 'poolnaming'),
}
return orig(ui, source, *args, **opts)
def extsetup(ui):
extensions.wrapfunction(bookmarks, '_getbkfile', getbkfile)
extensions.wrapfunction(bookmarks.bmstore, '_recordchange', recordchange)
extensions.wrapfunction(bookmarks.bmstore, '_writerepo', writerepo)
extensions.wrapcommand(commands.table, 'clone', clone)
def _hassharedbookmarks(repo):
"""Returns whether this repo has shared bookmarks"""
try:
shared = repo.vfs.read('shared').splitlines()
except IOError as inst:
if inst.errno != errno.ENOENT:
raise
return False
return hg.sharedbookmarks in shared
def getbkfile(orig, repo):
if _hassharedbookmarks(repo):
srcrepo = hg.sharedreposource(repo)
if srcrepo is not None:
# just orig(srcrepo) doesn't work as expected, because
# HG_PENDING refers repo.root.
try:
fp, pending = txnutil.trypending(repo.root, repo.vfs,
'bookmarks')
if pending:
# only in this case, bookmark information in repo
# is up-to-date.
return fp
fp.close()
except IOError as inst:
if inst.errno != errno.ENOENT:
raise
# otherwise, we should read bookmarks from srcrepo,
# because .hg/bookmarks in srcrepo might be already
# changed via another sharing repo
repo = srcrepo
# TODO: Pending changes in repo are still invisible in
# srcrepo, because bookmarks.pending is written only into repo.
# See also https://www.mercurial-scm.org/wiki/SharedRepository
return orig(repo)
def recordchange(orig, self, tr):
# Continue with write to local bookmarks file as usual
orig(self, tr)
if _hassharedbookmarks(self._repo):
srcrepo = hg.sharedreposource(self._repo)
if srcrepo is not None:
category = 'share-bookmarks'
tr.addpostclose(category, lambda tr: self._writerepo(srcrepo))
def writerepo(orig, self, repo):
# First write local bookmarks file in case we ever unshare
orig(self, repo)
if _hassharedbookmarks(self._repo):
srcrepo = hg.sharedreposource(self._repo)
if srcrepo is not None:
orig(self, srcrepo)