Match a revset pattern against repo.changegroup?

Matt Mackall mpm at selenic.com
Sun Oct 9 16:41:43 CDT 2011


On Sun, 2011-10-09 at 23:31 +0200, Angel Ezquerra wrote:
> On Sun, Oct 9, 2011 at 11:24 PM, Matt Mackall <mpm at selenic.com> wrote:
> > On Sun, 2011-10-09 at 23:14 +0200, Angel Ezquerra wrote:
> >> On Sun, Oct 9, 2011 at 10:51 PM, Matt Mackall <mpm at selenic.com> wrote:
> >> > On Sun, 2011-10-09 at 22:13 +0200, Angel Ezquerra wrote:
> >> >> Hi,
> >> >>
> >> >> is there an easy way to match a revset pattern against the received
> >> >> changegroup on the pretxnchangegroup hook?
> >> >
> >> > Check out repo.set(). This is slightly tricky because it doesn't (yet)
> >> > have a way to include a sub-expression:
> >> >
> >> > for ctx in repo.set("%%n:: and (%s)" % revsetexpr, firstincomingnode):
> >> >    print "bad", ctx.rev()
> >>
> >> Thank you!
> >>
> >> I was a bit confused by the %%n, until I read the docstring of the
> >> revset.formatspec function. For those who don't know, %n is equivalent
> >> to "hex(arg)".
> >>
> >> BTW, is there a better way to get the list of revisions that are being
> >> pushed during the pretxnchangegroup hook?
> >
> > It's a simple as taking the given node and finding all revisions
> > numerically after it. Due to the append-only rule, that's where all the
> > new changesets must be.
> 
> OK, that makes sense, thanks.
> 
> 
> > And that's just:
> >
> > repo.set('%n:', node)
> >
> > (note the one ':', my earlier set above is wrong)
> >
> > You don't really need contexts and a revset for this, of course:
> >
> > xrange(repo[node].rev(), repo['tip'] + 1)
> >
> 
> Is one method faster than the other? That is, is there a significant
> cost when using revision sets in this context?

The xrange method is slightly faster. But if it takes you a few minutes
to optimize something (or talk about optimizing something) by a few
microseconds and that code doesn't get run many many millions of times,
it's a false optimization. This code gets run... once per push.

-- 
Mathematics is the supreme nostalgia of our time.




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