[Bug 3628 - single transaction for graft with multiple revisions]

[Matt Mackall]

On Tue, 2015-09-29 at 20:38 +0200, Piotr Listkiewicz wrote:
> Up ,maybe anybody can help with this?

You probably shouldn't try to imitate the BTS robot's subject lines
because people like to ignore it.

> 2015-09-22 20:57 GMT+02:00 Piotr Listkiewicz <piotr.listkiewicz at gmail.com>:
> 
> > I took a look at issue: http://bz.selenic.com/show_bug.cgi?id=3628 . I
> > started working on it, i hoped that sth like:
> >
> > diff -r 836291420d53 -r 0861313845a8 mercurial/commands.py
> > --- a/mercurial/commands.py     Sat Sep 12 16:11:17 2015 -0700
> > +++ b/mercurial/commands.py     Tue Sep 22 20:47:36 2015 +0200
> > @@ -3578,8 +3578,11 @@
> >          if not revs:
> >              return -1
> >
> > -    wlock = repo.wlock()
> >      try:
> > +        wlock = repo.wlock()
> > +        lock = repo.lock()
> > +        tr = repo.transaction("graft")
> > +
> >          for pos, ctx in enumerate(repo.set("%ld", revs)):
> >              desc = '%d:%s "%s"' % (ctx.rev(), ctx,
> >                                     ctx.description().split('\n', 1)[0])
> > @@ -3636,8 +3639,10 @@
> >                  ui.warn(
> >                      _('note: graft of %d:%s created no changes to
> > commit\n') %
> >                      (ctx.rev(), ctx))
> > +
> > +        tr.close()
> >      finally:
> > -        wlock.release()
> > +        release(tr, lock, wlock)
> >
> > would work but its not. Problem with making graft transactional in such a
> > way is encountered when there are conflicts during merge - transaction is
> > rolled back before it gives a user chance to resolve merge commit.

The above is the sort of fix whoever marked it easy in the BTS (me?)
probably had in mind. But they probably hadn't considered the case of
transactions spanning multiple command executions (that don't exist
anywhere else in hg). So it is in fact a hard bug and will require
understanding the whole transaction mechanism and figuring out how to
extend it. I probably wouldn't work on this one.

-- 
Mathematics is the supreme nostalgia of our time.