Re: "bad revision" fetch error when fetching missing objects from partial clones

> I think it is actually a bug with pack-objects not sending the object,
> but it only seems to trigger with bitmaps. This works:
> 
>    git init repo
>    cd repo
> 
>    echo content >file
>    git add file
>    git commit -m base
> 
>    git config uploadpack.allowfilter true
>    git clone --no-local --bare --filter=blob:none . clone
> 
>    cd clone
>    git fetch origin $(git rev-parse HEAD:file)
> 
> But if I add a "git repack -adb" in the parent repository before the "cd
> clone", then I get:
> 
>    remote: Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
>    fatal: bad revision 'd95f3ad14dee633a758d2e331151e950dd13e4ed'
>    error: /home/peff/tmp/repo/. did not send all necessary objects
> 
> So presumably this is a bug in the bitmap-aware filtering code that is
> not present in the regular filter-traversing code. But what really
> puzzles me is that the result seems totally broken. Yet the test
> coverage in t5310 passes, and nobody has noticed on major sites like
> GitHub (which supports partial clones and most certainly has bitmaps
> enabled).