[MERGE] Implement hard-link support for branch and checkout

[Aaron Bentley]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Robert Collins wrote:
> On Wed, 2008-01-02 at 19:00 -0500, Aaron Bentley wrote:
> 
>> I don't want to make people shoot themselves in the foot, but holding
>> back this capability from those who could benefit is like cutting off
>> their feet so they don't shoot themselves in the foot.
> 
> I think this analogy is rather extreme.

I think it's extremely funny.  You thought I was going to say something
about making guns illegal, didn't you?

> You can have external scripts
> that hardlink identical files over arbitrary directory structures;
> they've been written before, and will generate better space savings

Creating the files and then hard-linking them
1. requires more free space (because the files are temporarily not
   hard-linked)
2. is slower (for one thing, general scripts don't know about Bazaar's
   cached SHA1s)
3. is less convenient

> than
> bzr knowing how to hardlink in the single special case of branch.

We're not talking about a just branch here.  The patch adds support to
checkout too, and I've got support ready for cbranch also.  You want
merge?  I can do merge, too.  Revert would just be a pain, though.

But more importantly, it's not a special case, it's a recommended
workflow: feature branches.  You branch (or cbranch), commit, maybe
merge, and submit.  I think we should promote this workflow, so I think
we should try to make it very convenient to use.  Just because we can do
it the inconvenient way doesn't mean we shouldn't do it the convenient
way.  People should feel free to branch at the drop of a hat.

Aaron
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFHfC5p0F+nu1YWqI0RAlnLAKCAvYR05nMPk7f7ejqprX/obTTXgQCdGmcy
YKNbY3XG8bLERJ1e9X3c4xI=
=JGO2
-----END PGP SIGNATURE-----