[PATCH V2] show: implement "stack" view

[Yuya Nishihara]

On Sat, 01 Jul 2017 22:39:40 -0700, Gregory Szorc wrote:
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1498973922 25200
> #      Sat Jul 01 22:38:42 2017 -0700
> # Node ID eaf601d0ea04ad80ee3d763cb3274286a780f16d
> # Parent  6d678ab1b10d0fddc73003d21aa3c7ec43194e2e
> show: implement "stack" view

Looks generally good to me, so queued, thanks.

> + at showview('stack', csettopic='stack')
> +def showstack(ui, repo, displayer):
> +    """current line of work"""
> +    wdirctx = repo['.']
> +    if wdirctx.rev() == nullrev:
> +        raise error.Abort(_('stack view only available when there is a '
> +                            'working directory'))
> +
> +    if wdirctx.phase() == phases.public:
> +        ui.write(_('(empty stack; working directory is a published '
> +                   'changeset)\n'))

"." isn't called "working directory", but "working directory parent".

> +    for rev in cl.descendants([wdirctx.rev()]):
> +        ctx = repo[rev]
> +
> +        # Will only happen if . is public.
> +        if ctx.phase() == phases.public:
> +            break
> +
> +        stackrevs.add(ctx.rev())
> +
> +        if len(ctx.children()) > 1:
> +            branchpointattip = True
> +            break

Maybe this is quadratic?

> +    stackrevs = list(reversed(sorted(stackrevs)))

could be sorted(reverse=True).

> +    try:
> +        cmdutil.findcmd('rebase', commands.table)
> +        haverebase = True
> +    except error.UnknownCommand:
> +        haverebase = False

Maybe AmbiguousCommand could be raised if there's no 'rebase', but 'rebasefoo'
and 'rebasebar'. But nobody would care.

> +def stackbase(ui, repo):
> +    # The histedit default base stops at public changesets, branchpoints,
> +    # and merges, which is exactly what we want for a stack.
> +    revs = scmutil.revrange(repo, [histeditdefaultrevset])

Perhaps repo.revs() can be used here since alias expansion shouldn't be
necessary.

> +    return revs.last() if revs else None

revs.last() is documented to return None if the set is empty.