Patchwork [4,of,4,V3,evolve-ext] metaedit: add support for folding commits while editing their metadata

# HG changeset patch
# User Siddharth Agarwal <sid0@fb.com>
# Date 1461003256 25200
#      Mon Apr 18 11:14:16 2016 -0700
# Node ID d39a22490ec843e9a08925996882ff1d1f6486a0
# Parent  625420da4048a1cdf1599a6b8fb8782713bd560f
metaedit: add support for folding commits while editing their metadata

This also allows us to accept multiple commits without dealing with the thorny
algorithmic and UI issues of editing multiple commits at once.

Crucially, it is different from 'hg fold --exact' in that it also allows
'folding' a single commit and rewriting its metadata. This is really useful to
have as a single logical operation, for example while preparing a series of
multiple local changesets that will need to be pushed as a single changeset.

Apart from the naming issue, this looks good to me, code-wise.

Are there other operations that make sense combined with metaedit, not 
just fold? Reorder, perhaps? And do we want a --roll as well, which 
simply takes the commit message from a selected commit in the set being 
folded together?

On 18/04/2016 19:14, Siddharth Agarwal wrote:
> # HG changeset patch
> # User Siddharth Agarwal <sid0@fb.com>
> # Date 1461003256 25200
> #      Mon Apr 18 11:14:16 2016 -0700
> # Node ID d39a22490ec843e9a08925996882ff1d1f6486a0
> # Parent  625420da4048a1cdf1599a6b8fb8782713bd560f
> metaedit: add support for folding commits while editing their metadata
>
> This also allows us to accept multiple commits without dealing with the thorny
> algorithmic and UI issues of editing multiple commits at once.
>
> Crucially, it is different from 'hg fold --exact' in that it also allows
> 'folding' a single commit and rewriting its metadata. This is really useful to
> have as a single logical operation, for example while preparing a series of
> multiple local changesets that will need to be pushed as a single changeset.
>
> diff --git a/hgext/evolve.py b/hgext/evolve.py
> --- a/hgext/evolve.py
> +++ b/hgext/evolve.py
> @@ -3151,14 +3151,18 @@ def fold(ui, repo, *revs, **opts):
>
>   @command('^metaedit',
>            [('r', 'rev', [], _("revision to edit")),
> +          ('', 'fold', None, _("also fold specified revisions into one")),
>            ] + commitopts + commitopts2,
>            _('hg metaedit [OPTION]... [-r] [REV]'))
>   def metaedit(ui, repo, *revs, **opts):
>       """edit commit information
>
> -    Edits the commit information for the specified revision. By default, edits
> +    Edits the commit information for the specified revisions. By default, edits
>       commit information for the working directory parent.
>
> +    With --fold, also folds multiple revisions into one if necessary. In this
> +    case, the given revisions must form a linear unbroken chain.
> +
>       .. container:: verbose
>
>        Some examples:
> @@ -3171,10 +3175,19 @@ def metaedit(ui, repo, *revs, **opts):
>
>            hg metaedit --user 'New User <new-email@example.com>'
>
> +     - Combine all draft revisions that are ancestors of foo but not of @ into
> +       one::
> +
> +         hg metaedit --fold 'draft() and only(foo,@)'
> +
> +       See :hg:`help phases` for more about draft revisions, and
> +       :hg:`help revsets` for more about the `draft()` and `only()` keywords.
>       """
>       revs = list(revs)
>       revs.extend(opts['rev'])
>       if not revs:
> +        if opts['fold']:
> +            raise error.Abort(_('revisions must be specified with --fold'))
>           revs = ['.']
>
>       wlock = lock = None
> @@ -3183,7 +3196,7 @@ def metaedit(ui, repo, *revs, **opts):
>           lock = repo.lock()
>
>           revs = scmutil.revrange(repo, revs)
> -        if len(revs) > 1:
> +        if not opts['fold'] and len(revs) > 1:
>               # TODO: handle multiple revisions. This is somewhat tricky because
>               # if we want to edit a series of commits:
>               #
> @@ -3192,18 +3205,21 @@ def metaedit(ui, repo, *revs, **opts):
>               # we need to rewrite a first, then directly rewrite b on top of the
>               # new a, then rewrite c on top of the new b. So we need to handle
>               # revisions in topological order.
> -            raise error.Abort(_('editing multiple revisions is not '
> -                                'currently supported'))
> -
> -        newunstable = _newdisallowedunstable(repo, revs)
> -        if newunstable:
> -            raise error.Abort(
> -                _('cannot edit commit information in the middle of a stack'),
> -                hint=_('%s will be affected') % repo[newunstable.first()])
> -        if repo.revs("%ld and public()", revs):
> -            raise error.Abort(_('cannot edit commit information for public '
> -                                'revisions'))
> -        root = head = repo[revs.first()]
> +            raise error.Abort(_('editing multiple revisions without --fold is '
> +                                'not currently supported'))
> +
> +        if opts['fold']:
> +            root, head = _foldcheck(repo, revs)
> +        else:
> +            newunstable = _newdisallowedunstable(repo, revs)
> +            if newunstable:
> +                raise error.Abort(
> +                    _('cannot edit commit information in the middle of a stack'),
> +                    hint=_('%s will be affected') % repo[newunstable.first()])
> +            if repo.revs("%ld and public()", revs):
> +                raise error.Abort(_('cannot edit commit information for public '
> +                                    'revisions'))
> +            root = head = repo[revs.first()]
>
>           wctx = repo[None]
>           p1 = wctx.p1()
> @@ -3217,7 +3233,12 @@ def metaedit(ui, repo, *revs, **opts):
>               if commitopts.get('message') or commitopts.get('logfile'):
>                   commitopts['edit'] = False
>               else:
> -                msgs = [head.description()]
> +                if opts['fold']:
> +                    msgs = ["HG: This is a fold of %d changesets." % len(allctx)]
> +                    msgs += ["HG: Commit message of changeset %s.\n\n%s\n" %
> +                             (c.rev(), c.description()) for c in allctx]
> +                else:
> +                    msgs = [head.description()]
>                   commitopts['message'] =  "\n".join(msgs)
>                   commitopts['edit'] = True
>
> @@ -3239,6 +3260,8 @@ def metaedit(ui, repo, *revs, **opts):
>           finally:
>               tr.release()
>
> +        if opts['fold']:
> +            ui.status('%i changesets folded\n' % len(revs))
>           if newp1 is not None:
>               hg.update(repo, newp1)
>       finally:
> diff --git a/tests/test-evolve.t b/tests/test-evolve.t
> --- a/tests/test-evolve.t
> +++ b/tests/test-evolve.t
> @@ -1468,11 +1468,26 @@ hg metaedit
>     $ hg metaedit -r 0
>     abort: cannot edit commit information for public revisions
>     [255]
> +  $ hg metaedit --fold
> +  abort: revisions must be specified with --fold
> +  [255]
> +  $ hg metaedit -r 0 --fold
> +  abort: cannot fold public revisions
> +  [255]
> +  $ hg metaedit '36 + 42' --fold
> +  abort: cannot fold non-linear revisions (multiple roots given)
> +  [255]
> +  $ hg metaedit '36::39 + 41' --fold
> +  abort: cannot fold non-linear revisions (multiple heads given)
> +  [255]
>   check that metaedit respects allowunstable
>     $ hg metaedit '.^' --config 'experimental.evolution=createmarkers, allnewcommands'
>     abort: cannot edit commit information in the middle of a stack
>     (c904da5245b0 will be affected)
>     [255]
> +  $ hg metaedit '18::20' --fold --config 'experimental.evolution=createmarkers, allnewcommands'
> +  abort: cannot fold chain not ending with a head or with branching
> +  [255]
>     $ hg metaedit --user foobar
>     0 files updated, 0 files merged, 0 files removed, 0 files unresolved
>     $ hg log --template '{rev}: {author}\n' -r '42:' --hidden
> @@ -1483,26 +1498,57 @@ check that metaedit respects allowunstab
>
>   TODO: support this
>     $ hg metaedit '.^::.'
> -  abort: editing multiple revisions is not currently supported
> +  abort: editing multiple revisions without --fold is not currently supported
>     [255]
>
> -no new commit is created here because the date is the same
> -  $ HGEDITOR=cat hg metaedit
> +  $ HGEDITOR=cat hg metaedit '.^::.' --fold
> +  HG: This is a fold of 2 changesets.
> +  HG: Commit message of changeset 41.
> +
> +  amended
> +
> +  HG: Commit message of changeset 43.
> +
>     will be evolved safely
>
>
> +
>     HG: Enter commit message.  Lines beginning with 'HG:' are removed.
>     HG: Leave message empty to abort commit.
>     HG: --
> -  HG: user: foobar
> +  HG: user: test
>     HG: branch 'default'
>     HG: changed a
> +  HG: changed newfile
> +  2 changesets folded
> +  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
> +
> +  $ glog -r .
> +  @  44:41bf1183869c@default(draft) amended
> +  |
> +  ~
> +
> +no new commit is created here because the date is the same
> +  $ HGEDITOR=cat hg metaedit
> +  amended
> +
> +
> +  will be evolved safely
> +
> +
> +  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
> +  HG: Leave message empty to abort commit.
> +  HG: --
> +  HG: user: test
> +  HG: branch 'default'
> +  HG: changed a
> +  HG: changed newfile
>     nothing changed
>
>     $ glog -r '.^::.'
> -  @  43:62353add3dfb@default(draft) will be evolved safely
> +  @  44:41bf1183869c@default(draft) amended
>     |
> -  o  41:34ae045ec400@default(draft) amended
> +  o  36:43c3f5ef149f@default(draft) add uu
>     |
>     ~
>
> @@ -1510,15 +1556,22 @@ TODO: don't create a new commit in this
>     $ hg metaedit --config defaults.metaedit=
>     0 files updated, 0 files merged, 0 files removed, 0 files unresolved
>     $ hg log -r '.^::.' --template '{rev}: {desc|firstline}\n'
> -  41: amended
> -  44: will be evolved safely
> +  36: add uu
> +  45: amended
>
>     $ hg up .^
> -  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
> -  $ hg metaedit --user foobar2 44
> +  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
> +  $ hg metaedit --user foobar2 45
>     $ hg log --template '{rev}: {author}\n' -r '42:' --hidden
>     42: test
>     43: foobar
> -  44: foobar
> -  45: foobar2
> -  $ hg diff -r 44 -r 45 --hidden
> +  44: test
> +  45: test
> +  46: foobar2
> +  $ hg diff -r 45 -r 46 --hidden
> +
> +'fold' one commit
> +  $ hg metaedit 39 --fold --user foobar3
> +  1 changesets folded
> +  $ hg log -r 47 --template '{rev}: {author}\n'
> +  47: foobar3
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On 4/25/16 15:03, Simon Farnsworth wrote:
> Apart from the naming issue, this looks good to me, code-wise.
>
> Are there other operations that make sense combined with metaedit, not 
> just fold? Reorder, perhaps? And do we want a --roll as well, which 
> simply takes the commit message from a selected commit in the set 
> being folded together? 


Reorder can in principle involve working copy merges, so it's probably 
not the best fit.

--roll sounds interesting but you can achieve it with something like 
--logfile <(hg log -r <commit> -T '{desc}'). I'd wait for it to be 
implemented for 'hg commit --amend' and similar, though.