Re: [PATCH] archive: let remote clients get reachable commits

On Fri, Feb 22, 2013 at 09:10:46AM -0800, Junio C Hamano wrote:

I personally think that it is OK to limit the scope to expressions
that start from the tip of ref and expressions that start with the
SHA-1 at the tip of ref, e.g.

    master~12:Documentation
    v2.6.11:arch/alpha
    5dc01c595e6c6ec9ccda	# tag v2.6.11
    26791a8bcf0e6d33f43a:arch	# tag v2.6.12
    26791a8bcf0~12:arch		# starting at 26791a8b and dig down

are OK, while forbidding the following:

    c39ae07f393806ccf406        # tree of tag v2.6.11
    9ee1c939d1cb936b1f98	# commit v2.6.12^0
    9ee1c939d1cb936b1f98:	# tree of commit v2.6.12^0
    9ee1c939d1cb936b1f98:arch	# subtree of commit v2.6.12^0

which will make it significantly easier to implement the necessary
validation in a robust way.

How are you proposing to verify master~12 in that example? Because
during parsing, it starts with "master", and we remember that? Or
because you are doing a reachability traversal on all refs after we
parse?

-Peff