bug#22032: 24.3; VC doesn't handle hg hidden revisions

[Dmitry Gutov]

On 12/16/2015 05:02 AM, Andy Moreton wrote:

> > If there's a direct counterpart to 'git rev-parse 59951^', it would be handy
> > here.
>
> You mean like the "hg id" line in the example above ?

Um, yes. Thanks for the explanation, I've pushed the new definition of 
vc-hg-previous-revision that uses 'hg id -n -r 123^' to emacs-25.

It seems to work fine, if a little surprising for merge commits when 
vc-hg-log-graph is nil (which it is by default). Also, calling Hg is not 
free, and adds ~120 ms on my machine.

Glenn, could you if it solves the hidden revision problem as well?