Re: 1.5.6.5 fails to clone git.kernel.org/[...]/rostedt/linux-2.6-rt

Hi,

On Fri, 9 Jan 2009, Junio C Hamano wrote:

I think we lost the alternate object store support when git-fetch was 
rewritten from the original shell script (that did support fetching from 
such a repository over rsync:// transport) to a reimplementation in C, 
with commit b888d61 (Make fetch a builtin, 2007-09-10).

Later, cd547b4 (fetch/push: readd rsync support, 2007-10-01) attempted to
resurrect some rsync support (b888d61 lost rsync support completely for
git-fetch), but introduced these lines in transport.c:

	/* NEEDSWORK: handle one level of alternates */
	result = run_command(&rsync);

Indeed... And I know who's responsible for those lines.

However, I am swamped with work these days, and my Git time budget was 
_way_ overspent what with the recent patches.

So whoever would like to give it a go, go wild.

This is actually a very fine opportunity for people to get involved who 
always wanted to; it is a relatively low-hanging fruit.

It should just be a matter of getting objects/info/alternates (one can 
easily reuse a large part of the args[] array filled before the quoted 
code) into a temporary file.

If that does not succeed, return 0, otherwise fetch those objects, too 
(again reusing most of the args[] array).

It is that easy because objects as well as packs are immutable, so we can 
just build the union of objects/packs from the remote and its alternate.

Then all which is left to do is to add a test case to t/t5510-fetch.sh, 
and you're set.

As there are already test cases for rsync:// in it, it should be as simple 
as putting an empty file into a newly created directory, create an 
alternate for the "remote" pointing to the directory, fetching, and 
testing that the empty file was copied.

That's possible because rsync:// is dumb and does not verify the files it 
copied.

Oh, and don't forget to remove the NEEDSWORK comment :-)

And now I'm curious who's up for it...

Ciao,
Dscho