# histedit.py - interactive history editing for mercurial

#

# Copyright 2009 Augie Fackler <raf@durin42.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""interactive history editing

With this extension installed, Mercurial gains one new command: histedit. Usage

is as follows, assuming the following history::

 @  3[tip]   7c2fd3b9020c   2009-04-27 18:04 -0500   durin42

 |    Add delta

 |

 o  2   030b686bedc4   2009-04-27 18:04 -0500   durin42

 |    Add gamma

 |

 o  1   c561b4e977df   2009-04-27 18:04 -0500   durin42

 |    Add beta

 |

 o  0   d8d2fcd0e319   2009-04-27 18:04 -0500   durin42

      Add alpha

If you were to run ``hg histedit c561b4e977df``, you would see the following

file open in your editor::

 pick c561b4e977df Add beta

 pick 030b686bedc4 Add gamma

 pick 7c2fd3b9020c Add delta

 # Edit history between c561b4e977df and 7c2fd3b9020c

 #

 # Commits are listed from least to most recent

 #

 # Commands:

 #  p, pick = use commit

 #  e, edit = use commit, but stop for amending

 #  f, fold = use commit, but combine it with the one above

 #  d, drop = remove commit from history

 #  m, mess = edit message without changing commit content

 #

In this file, lines beginning with ``#`` are ignored. You must specify a rule

for each revision in your history. For example, if you had meant to add gamma

before beta, and then wanted to add delta in the same revision as beta, you

would reorganize the file to look like this::

 pick 030b686bedc4 Add gamma

 pick c561b4e977df Add beta

 fold 7c2fd3b9020c Add delta

 # Edit history between c561b4e977df and 7c2fd3b9020c

 #

 # Commits are listed from least to most recent

 #

 # Commands:

 #  p, pick = use commit

 #  e, edit = use commit, but stop for amending

 #  f, fold = use commit, but combine it with the one above

 #  d, drop = remove commit from history

 #  m, mess = edit message without changing commit content

 #

At which point you close the editor and ``histedit`` starts working. When you

specify a ``fold`` operation, ``histedit`` will open an editor when it folds

those revisions together, offering you a chance to clean up the commit message::

 Add beta

 ***

 Add delta

Edit the commit message to your liking, then close the editor. For

this example, let's assume that the commit message was changed to

``Add beta and delta.`` After histedit has run and had a chance to

remove any old or temporary revisions it needed, the history looks

like this::

 @  2[tip]   989b4d060121   2009-04-27 18:04 -0500   durin42

 |    Add beta and delta.

 |

 o  1   081603921c3f   2009-04-27 18:04 -0500   durin42

 |    Add gamma

 |

 o  0   d8d2fcd0e319   2009-04-27 18:04 -0500   durin42

      Add alpha

Note that ``histedit`` does *not* remove any revisions (even its own temporary

ones) until after it has completed all the editing operations, so it will

probably perform several strip operations when it's done. For the above example,

it had to run strip twice. Strip can be slow depending on a variety of factors,

so you might need to be a little patient. You can choose to keep the original

revisions by passing the ``--keep`` flag.

The ``edit`` operation will drop you back to a command prompt,

allowing you to edit files freely, or even use ``hg record`` to commit

some changes as a separate commit. When you're done, any remaining

uncommitted changes will be committed as well. When done, run ``hg

histedit --continue`` to finish this step. You'll be prompted for a

new commit message, but the default commit message will be the

original message for the ``edit`` ed revision.

The ``message`` operation will give you a chance to revise a commit

message without changing the contents. It's a shortcut for doing

``edit`` immediately followed by `hg histedit --continue``.

If ``histedit`` encounters a conflict when moving a revision (while

handling ``pick`` or ``fold``), it'll stop in a similar manner to

``edit`` with the difference that it won't prompt you for a commit

message when done. If you decide at this point that you don't like how

much work it will be to rearrange history, or that you made a mistake,

you can use ``hg histedit --abort`` to abandon the new changes you

have made and return to the state before you attempted to edit your

history.

If we clone the histedit-ed example repository above and add four more

changes, such that we have the following history::

   @  6[tip]   038383181893   2009-04-27 18:04 -0500   stefan

   |    Add theta

   |

   o  5   140988835471   2009-04-27 18:04 -0500   stefan

   |    Add eta

   |

   o  4   122930637314   2009-04-27 18:04 -0500   stefan

   |    Add zeta

   |

   o  3   836302820282   2009-04-27 18:04 -0500   stefan

   |    Add epsilon

   |

   o  2   989b4d060121   2009-04-27 18:04 -0500   durin42

   |    Add beta and delta.

   |

   o  1   081603921c3f   2009-04-27 18:04 -0500   durin42

   |    Add gamma

   |

   o  0   d8d2fcd0e319   2009-04-27 18:04 -0500   durin42

        Add alpha

If you run ``hg histedit --outgoing`` on the clone then it is the same

as running ``hg histedit 836302820282``. If you need plan to push to a

repository that Mercurial does not detect to be related to the source

repo, you can add a ``--force`` option.

"""

try:

    import cPickle as pickle

    pickle.dump # import now

except ImportError:

    import pickle

import os

import sys

from mercurial import cmdutil

from mercurial import discovery

from mercurial import error

from mercurial import copies

from mercurial import context

from mercurial import hg

from mercurial import node

from mercurial import repair

from mercurial import scmutil

from mercurial import util

from mercurial import obsolete

from mercurial import merge as mergemod

from mercurial.lock import release

from mercurial.i18n import _

cmdtable = {}

command = cmdutil.command(cmdtable)

testedwith = 'internal'

# i18n: command names and abbreviations must remain untranslated

editcomment = _("""# Edit history between %s and %s

#

# Commits are listed from least to most recent

#

# Commands:

#  p, pick = use commit

#  e, edit = use commit, but stop for amending

#  f, fold = use commit, but combine it with the one above

#  d, drop = remove commit from history

#  m, mess = edit message without changing commit content

#

""")

def commitfuncfor(repo, src):

    """Build a commit function for the replacement of <src>

    This function ensure we apply the same treatment to all changesets.

    - Add a 'histedit_source' entry in extra.

    Note that fold have its own separated logic because its handling is a bit

    different and not easily factored out of the fold method.

    """

    phasemin = src.phase()

    def commitfunc(**kwargs):

        phasebackup = repo.ui.backupconfig('phases', 'new-commit')

        try:

            repo.ui.setconfig('phases', 'new-commit', phasemin,

                              'histedit')

            extra = kwargs.get('extra', {}).copy()

            extra['histedit_source'] = src.hex()

            kwargs['extra'] = extra

            return repo.commit(**kwargs)

        finally:

            repo.ui.restoreconfig(phasebackup)

    return commitfunc

def applychanges(ui, repo, ctx, opts):

    """Merge changeset from ctx (only) in the current working directory"""

    wcpar = repo.dirstate.parents()[0]

    if ctx.p1().node() == wcpar:

        # edition ar "in place" we do not need to make any merge,

        # just applies changes on parent for edition

        cmdutil.revert(ui, repo, ctx, (wcpar, node.nullid), all=True)

        stats = None

    else:

        try:

            # ui.forcemerge is an internal variable, do not document

            repo.ui.setconfig('ui', 'forcemerge', opts.get('tool', ''),

                              'histedit')

            stats = mergemod.update(repo, ctx.node(), True, True, False,

                                    ctx.p1().node())

        finally:

            repo.ui.setconfig('ui', 'forcemerge', '', 'histedit')

        repo.setparents(wcpar, node.nullid)

        repo.dirstate.write()

        # fix up dirstate for copies and renames

    cmdutil.duplicatecopies(repo, ctx.rev(), ctx.p1().rev())

    return stats

def collapse(repo, first, last, commitopts):

    """collapse the set of revisions from first to last as new one.

    Expected commit options are:

        - message

        - date

        - username

    Commit message is edited in all cases.

    This function works in memory."""

    ctxs = list(repo.set('%d::%d', first, last))

    if not ctxs:

        return None

    base = first.parents()[0]

    # commit a new version of the old changeset, including the update

    # collect all files which might be affected

    files = set()

    for ctx in ctxs:

        files.update(ctx.files())

    # Recompute copies (avoid recording a -> b -> a)

    copied = copies.pathcopies(base, last)

    # prune files which were reverted by the updates

    def samefile(f):

        if f in last.manifest():

            a = last.filectx(f)

            if f in base.manifest():

                b = base.filectx(f)

                return (a.data() == b.data()

                        and a.flags() == b.flags())

            else:

                return False

        else:

            return f not in base.manifest()

    files = [f for f in files if not samefile(f)]

    # commit version of these files as defined by head

    headmf = last.manifest()

    def filectxfn(repo, ctx, path):

        if path in headmf:

            fctx = last[path]

            flags = fctx.flags()

            mctx = context.memfilectx(repo,

                                      fctx.path(), fctx.data(),

                                      islink='l' in flags,

                                      isexec='x' in flags,

                                      copied=copied.get(path))

            return mctx

        raise IOError()

    if commitopts.get('message'):

        message = commitopts['message']

    else:

        message = first.description()

    user = commitopts.get('user')

    date = commitopts.get('date')

    extra = commitopts.get('extra')

    parents = (first.p1().node(), first.p2().node())

    new = context.memctx(repo,

                         parents=parents,

                         text=message,

                         files=files,

                         filectxfn=filectxfn,

                         user=user,

                         date=date,

                         extra=extra,

                         editor=cmdutil.getcommiteditor(edit=True))

    return repo.commitctx(new)

def pick(ui, repo, ctx, ha, opts):

    oldctx = repo[ha]

    if oldctx.parents()[0] == ctx:

        ui.debug('node %s unchanged\n' % ha)

        return oldctx, []

    hg.update(repo, ctx.node())

    stats = applychanges(ui, repo, oldctx, opts)

    if stats and stats[3] > 0:

        raise error.InterventionRequired(_('Fix up the change and run '

                                           'hg histedit --continue'))

    # drop the second merge parent

    commit = commitfuncfor(repo, oldctx)

    n = commit(text=oldctx.description(), user=oldctx.user(),

               date=oldctx.date(), extra=oldctx.extra())

    if n is None:

        ui.warn(_('%s: empty changeset\n')

                     % node.hex(ha))

        return ctx, []

    new = repo[n]

    return new, [(oldctx.node(), (n,))]

def edit(ui, repo, ctx, ha, opts):

    oldctx = repo[ha]

    hg.update(repo, ctx.node())

    applychanges(ui, repo, oldctx, opts)

    raise error.InterventionRequired(

        _('Make changes as needed, you may commit or record as needed now.\n'

          'When you are finished, run hg histedit --continue to resume.'))

def fold(ui, repo, ctx, ha, opts):

    oldctx = repo[ha]

    hg.update(repo, ctx.node())

    stats = applychanges(ui, repo, oldctx, opts)

    if stats and stats[3] > 0:

        raise error.InterventionRequired(

            _('Fix up the change and run hg histedit --continue'))

    n = repo.commit(text='fold-temp-revision %s' % ha, user=oldctx.user(),

                    date=oldctx.date(), extra=oldctx.extra())

    if n is None:

        ui.warn(_('%s: empty changeset')

                     % node.hex(ha))

        return ctx, []

    return finishfold(ui, repo, ctx, oldctx, n, opts, [])

def finishfold(ui, repo, ctx, oldctx, newnode, opts, internalchanges):

    parent = ctx.parents()[0].node()

    hg.update(repo, parent)

    ### prepare new commit data

    commitopts = opts.copy()

    # username

    if ctx.user() == oldctx.user():

        username = ctx.user()

    else:

        username = ui.username()

    commitopts['user'] = username

    # commit message

    newmessage = '\n***\n'.join(

        [ctx.description()] +

        [repo[r].description() for r in internalchanges] +

        [oldctx.description()]) + '\n'

    commitopts['message'] = newmessage

    # date

    commitopts['date'] = max(ctx.date(), oldctx.date())

    extra = ctx.extra().copy()

    # histedit_source

    # note: ctx is likely a temporary commit but that the best we can do here

    #       This is sufficient to solve issue3681 anyway

    extra['histedit_source'] = '%s,%s' % (ctx.hex(), oldctx.hex())

    commitopts['extra'] = extra

    phasebackup = repo.ui.backupconfig('phases', 'new-commit')

    try:

        phasemin = max(ctx.phase(), oldctx.phase())

        repo.ui.setconfig('phases', 'new-commit', phasemin, 'histedit')

        n = collapse(repo, ctx, repo[newnode], commitopts)

    finally:

        repo.ui.restoreconfig(phasebackup)

    if n is None:

        return ctx, []

    hg.update(repo, n)

    replacements = [(oldctx.node(), (newnode,)),

                     (ctx.node(), (n,)),

                     (newnode, (n,)),

                    ]

    for ich in internalchanges:

        replacements.append((ich, (n,)))

    return repo[n], replacements

def drop(ui, repo, ctx, ha, opts):

    return ctx, [(repo[ha].node(), ())]