Re: [PATCH] receive-pack, fetch-pack: reject bogus pack that records objects twice

On Fri, Nov 18, 2011 at 02:33, Jeff King [off-list ref] wrote:

On Wed, Nov 16, 2011 at 10:04:13PM -0800, Junio C Hamano wrote:

quoted

When receive-pack & fetch-pack are run and store the pack obtained over
the wire to a local repository, they internally run the index-pack command
with the --strict option. Make sure that we reject incoming packfile that
records objects twice to avoid spreading such a damage.

If we are fixing a thin pack (which should be the case most of the
time), we are rewriting the packfile anyway. Shouldn't we just omit
the duplicate?

I guess I'm a little confused about what is generating these duplicates.
A buggy git? A malicious server? Bad luck?

A buggy Git. We found a case where JGit could generate duplicate
objects in the pack stream during a clone. The resulting client
worked... until it tried to do `git gc` or really any sort of `git
pack-objects`.

In my opinion, a pack should never contain duplicate objects. Its a
buggy remote that sends them. What I like about this patch is it stops
and tells the user the remote is broken, which it is.