Re: 2.6.17-rc6-mm2

[Linus Torvalds <torvalds@osdl.org>]

On Fri, 16 Jun 2006, Goo GGooo wrote:
> 
> That's confusing - I believed all protocols should behave the same way...?

Not really. The primary protocol is the native git one, and the others try 
to do a best effort, but the http protocol really can't do a very good 
job unless the server side has run "git update-server-info" to help the 
http client along.

I suspect that the -mm git tree simply doesn't do that. In fact, even the 
main tree didn't use to do it, but I finally just broke down and added the 
proper hook to make it always do it automatically when I push.

(In case Andrew wants to do that, the way to do it is:

	echo -e "#!/bin/sh\nexec git-update-server-info" > hooks/post-update
	chmod +x hooks/post-update

inside the git repository - all it will do is always execute that script, 
and this "git-update-server-info", after you've updated the repo).

Finally, the rsync protocol just copies all objects over, and since it 
doesn't even know _which_ objects it is getting, it doesn't do the normal 
tag following that the native git protocol does.

So to recap:
 - http is fundamentally weaker, and needs some server-side help to work
 - rsync is fine for the initial clone, but doesn't actually know what 
   it's doing, so the end result can actually even be a corrupted 
   repository, because you happened to rsync just as it was updating.
 - the native git protocol generally should be considered the golden 
   standard, where the other ones are just fallbacks in case of problems 
   (like firewalls that don't let git:// through, or more commonly hosted 
   servers that don't do the git protocol at all).

Which hopefully clarifies the issue a bit.

		Linus