Re: [PATCH] Shallow clone: low level machinery.

Hi,

On Tue, 31 Jan 2006, Junio C Hamano wrote:

Johannes Schindelin [off-list ref] writes:

quoted

Worse, you cannot pull from older servers into shallow repos.

"have X" means different thing if you do not have matching
grafts information, so I suspect that is fundamentally
unsolvable.

If the shallow-capable client could realize that the server is not 
shallow-capable *and* the local repo is shallow, and refuse to operate 
(unless called with "-f", in which case the result may or may not be a 
broken repo, which has to be fixed up manually by copying 
over ORIG_HEAD to HEAD).

Of course, the client has to know that the local repo is shallow, which it 
must not determine by looking at the grafts file.
 

I am not sure you can convince "git-rev-list ^A" to mean "not at
A but things before that is still interesting", especially when
you give many other heads to start traversing from, but if you
can, then you can do things at rev-list command line parameter
level without doing the "exchange and use the same grafts"
trickery.  That _might_ be easier to implement but I do not see
an obvious correctness guarantee in the approach.

If you introduce a different "have X" -- like "have-no-parent X" -- and 
teach git-rev-list that "~A" means "traverse the tree of A, but not A's 
parents", you'd basically have everything you need, right?

Implementation bugs aside, it is obvious the things _would_ work 
correctly with "exchange and use the same grafts" approach.

Yes, I agree. But again, the local repo has to know which grafts were 
introduced by making the repo shallow.

Ciao,
Dscho