Re: Passing commit IDs to git-archive

From: Jeff King <peff@peff.net>
Date: Mar 12, 2012, 11:47 UTC
Message-ID: <20120312114742.GC12921@sigill.intra.peff.net>
In-Reply-To: <8fb14091-99dc-4383-9cab-5bf508e0a554@mail>

On Fri, Mar 09, 2012 at 05:14:05PM -0500, Stephen Bash wrote:

Show 6 quoted lines

> on Mac OS 10.6.8 (obviously this is local testing, the goal is to use
> ssh remotely).  After parsing the error "no such ref" I attempted the
> same operation using master as the tree-ish and archive worked as
> expected (either specifying the path separately or using the colon
> syntax to reference the tree directly).  Is there a reason git-archive
> requires a named ref rather than just a commit (or tree) ID?

Yes; generally git repositories do not allow clients to access arbitrary sha1s. Instead, they require that the requested objects be accessible by a ref.

git-archive was not properly enforcing this, and was changed recently to allow only refs by name, as well as sub-trees of refs (e.g., HEAD:subdir/). That means we do disallow an arbitrary commit or tree sha1, even if it is reachable from the advertised refs.

> would it be difficult to patch git-upload-archive to use the IDs?  I
> could use tags for the ref, but in my case would result in almost
> every commit being a tag which seems wasteful.

Doing it right is a bit expensive, because in the general case (somebody requested a tree sha1), we would need to traverse every tree of every commit to see if it is reachable.

We could potentially implement a more restricted set of rules, allowing "<commit>:<subdir>" and checking that <commit> is reachable. That would disallow an arbitrary tree sha1, but I suspect it would cover the common use case (i.e., you want to get the tree, or even a subtree, of a particular revision).

-Peff