sparse fetch, was Re: [PATCH 08/12] git-clone: support --path to do sparse clone

Hi,

On Thu, 24 Jul 2008, Jeff King wrote:

As a user, I would expect "sparse clone" to also be sparse on the 
fetching. That is, to not even bother fetching tree objects that we are 
not going to check out. But that is a whole other can of worms from 
local sparseness, so I think it is worth saving for a different series.

I think this is not even worth of a series.  Sure, it would have benefits 
for those who want sparse checkouts.  But it comes for a high price on 
everyone else:

- security issues (you'd need to open the git protocol to give you 
  something else than a ref, _including_ refs that were deleted)

- performance issues (the server would have to do a lot more, faking 
  commits, or in the alternative serving a gazillion more sessions if the 
  client does the reconstruction)

... and I am sure there are tons more issues.

Ciao,
Dscho