[PATCH] revset: introduce the summary predicate

[Yuya Nishihara]

On Wed, 11 Jan 2017 23:15:28 +0900, Yuya Nishihara wrote:
> On Tue, 10 Jan 2017 20:09:45 -0500, Matt Harbison wrote:
> > >> I've missed that '{firstline}' proposal from Sean, can you point me at  
> > >> it? (or summarize it ?)
> > >
> > > Not a proposal, so much as historical knowledge about the template?
> > >
> > > https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-January/092099.html
> 
> I thought that the proposal was something like
> search_in_template_output('re:issue\d+', '{desc|firstline'}').

For future readers, this could be a security risk (without safe=False),
because:

 a) hgweb supports most revsets (which are marked safe=True.)
 b) template may expose more information than revset knows (e.g. we might
    add {env} keyword)