On Wed, Nov 21 2018, Junio C Hamano wrote: > * "git rebase" and "git rebase -i" have been reimplemented in C. Here's another regression in the C version (and rc1), note: the sha1collisiondetection is just a stand in for "some repo": ( rm -rf /tmp/repo && git init /tmp/repo && cd /tmp/repo && for c in 1 2 do touch $c && git add $c && git commit -m"add $c" done && git remote add origin https://github.com/cr-marcstevens/sha1collisiondetection.git && git fetch && git branch --set-upstream-to origin/master && git rebase -i ) The C version will die with "fatal: unable to read tree 0000000000000000000000000000000000000000". Running this with rebase.useBuiltin=false does the right thing and rebases as of the merge base of the two (which here is the root of the history). I wasn't trying to stress test rebase. I was just wanting to rebase a history I was about to force-push after cleaning it up, hardly an obscure use-case. So [repeat last transmission in https://public-inbox.org/git/87y39w1wc2.fsf@xxxxxxxxxxxxxxxxxxx/ ]