(Almost) all extensions together in one place

[Greg Ward]

On 03 April 2011, timeless said:
> So, the trick to making happy minimal subrepos is to make sure all
> lines in .hgsubstate list the null revision.
> 
> the result is that you're just a directory of sources instead of an
> authoritative index of "current" for them.
> 
> it also means that when something fails to do something important it
> doesn't break the checkout or update or whatever.
> 
> this is also how you work around artemis being annoying.

Yeah, that's a workaround for this problem.  But allextensions is
really intended so that we can quickly and easily audit the universe
of existing extensions when we're contemplating some API change.  If
the latest source code isn't right there at your fingertips, then it's
not "quick and easy". 

Yes, I know that this is a bit of an awkward fit for subrepos, since I
want allextensions to track the latest upstream of everything.  So
periodically someone has to "hg pull -u" in every subrepo and commit
the resulting .hgsubstate.  Well, at least that action is explicitly
recorded in history.

BTW, note that Adrian's fix to Artemis was quickly accepted, so *that*
problem should be fixed.  IMHO that is the ideal way to proceed.

        Greg