view hgext/record.py @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

# 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 = 'ships-with-hg-core'


@command("record",
         # same options as commit + white space diff options
        [c for c in commands.table['^commit|ci'][1][:]
            if c[1] != "interactive"] + cmdutil.diffwsopts,
          _('hg record [OPTION]... [FILE]...'))
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(_('running non-interactively, use %s instead') %
                         'commit')

    opts["interactive"] = True
    overrides = {('experimental', 'crecord'): False}
    with ui.configoverride(overrides, '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('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('qrecord',
    [],
    _('hg qrecord [OPTION]... PATCH [FILE]...'),
    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('qnew', ui, repo, patch, *pats, **opts)

def _qrecord(cmdsuggest, ui, repo, patch, *pats, **opts):
    try:
        mq = extensions.find('mq')
    except KeyError:
        raise error.Abort(_("'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 = {('experimental', 'crecord'): False}
    with ui.configoverride(overrides, 'record'):
        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('mq')
    except KeyError:
        return

    cmdtable["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['^qnew'][1][:] + cmdutil.diffwsopts,
         _('hg qrecord [OPTION]... PATCH [FILE]...'))

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

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