news from the topic experiment

[Jun Wu]

Excerpts from Sean Farley's message of 2016-09-22 18:18:05 -0700:
> Jun Wu <quark at fb.com> writes:
> 
> > Excerpts from Sean Farley's message of 2016-09-22 17:30:34 -0700:
> >> Completely false. Take a look at the hgtopics repo:
> >> 
> >> $ hg log --debug -vr 093a | grep "\(topic=\|phase\)"
> >> phase:       public
> >> extra:       topic=stackheader
> >
> > I admit I didn't look into the details carefully. Sorry for that.
> >
> > I think the major difference is the "local" vs "global" part. I do think
> > having the ability to give changesets private labels locally can be useful -
> > that's probably another extension other than "topic".
> 
> I would definitely agree it is something else besides "topics". It might
> not appear so but I would definitely be interested in your ideas for
> this because I think it would help use provide something like "pull
> request refs" on Bitbucket for Mercurial.

I mistakenly thought "topic" was "private lightweight named branch". But
it isn't. Since there are 3 concepts already, I don't think it is worth to
invest on a fourth thing which will further clutter the interface and
confuse people, although it might be useful in some cases.

Part of the motivation to find a bookmark replacement (at fb) is things like
local bookmarks pointing to public changesets can confuse new users. The
reason bookmarks are used is partially because some arcanist commands
require an active bookmark. We may want to change those arcanist commands,
and just let new users use hashes or "Dxxxx" aliases.

In the future when creating a new working directory is cheap because of
fuse, we may hide those concepts and use different filesystem paths to
represent different features being worked on.