[BUG] rebase not recovering gracefully from repack error

(patches|REBASE 8/9)$ git rebase --continue
Applying: Check for __unix__ instead of __linux
Applying: Completely disable crash handler on archs other than i386 and amd64
Auto packing the repository for optimum performance. You may also
run "git gc" manually. See "git help gc" for more information.
error: Could not read a7d470051f53f4e4c9247df752583868a79ec70b
fatal: Failed to traverse parents of commit e6d2f264969207e337953717c260d37daa0a8554
error: failed to run repack
(patches|REBASE 10/9)$ cat .git/rebase-apply/next 
10
(patches|REBASE 10/9)$ 

The last patch has been dealt with and I consider the rebase done. Rebase would be bombing out without cleaning behind it when the auto repack fails ?

On another aspect, I find the repack error is suspect: "git fsck --no-dangling" has nothing to complain about, and the missing commit is the real ancestor of a grafted commit. I suppose it has been gc'd by a buggy git version, as I recall seeing such a fix on the list some time ago. (yes, I shouldn't be using grafts any more, but that particular one dates back to 2006 ;)