> On large repositories with lots of tags - git wire protocol v2 fails > to fetch shallow changes, it fails with error `pack has XXX unresolved > deltas`. Unfortunately I didn't find easy way to reproduce it except > cloning+fetching chromium repository, the way jenkins does. > Reproduction steps:
[snip] Thanks for your bug report and reproduction steps. I managed to reproduce your issue and took a look. The main issue seems to be that with v2, upload-pack doesn't pass "--shallow X" to pack-objects (the write_one_shallow() callback is never called, even if I change the "if (shallow_nr)" to "if (1)"), so pack-objects probably doesn't know that some objects cannot be used as delta bases. (With v0, write_one_shallow() is indeed called.) The issue probably lies in how v0 and v2 handle client-provided shallows differently. There also seems to be another issue in that negotiation occurs differently in these 2 protocols - I see the full list of "have" lines being sent in the final request to the server in v0, but a very limited list in v2. This might be because of the ref prefix limiting in v2, but I haven't fully investigated it. I'll look some more into this.
