[MERGE #102747] pre_commit hook

[Nam Nguyen]

On 9/3/07, Robert Collins <robertc at robertcollins.net> wrote:
> On Sun, 2007-09-02 at 20:27 -0400, Ian Clatworthy wrote:
> > Ian Clatworthy has voted approve.
> > Status is now: Semi-approved
>
> I'm curious if anyone has benchmarked this on huge trees (with no
> pre-commit plugin present).
>
> I'd like to ensure it does not add a measureable impact.

With a pre_commit hook registered,
future_tree.changes_from(basis_tree) is probably the biggest CPU eater
here. Without a pre_commit hook, I find no  reason for more than 0.5%
slow down. Then again, I have not huge trees to measure. I'm curious
to know if the numbers come out in contrast.

Cheers
Nam