Date: Sat, 13 Aug 2005 22:16:02 -0700 (PDT) From: Linus Torvalds To: Steve French cc: git@vger.kernel.org Subject: Re: sending changesets from the middle of a git tree Abstract: In this article, Linus demonstrates how a broken commit in a sequence of commits can be removed by rewinding the head and reapplying selected changes. On Sat, 13 Aug 2005, Linus Torvalds wrote: > That's correct. Same things apply: you can move a patch over, and create a > new one with a modified comment, but basically the _old_ commit will be > immutable. Let me clarify. You can entirely _drop_ old branches, so commits may be immutable, but nothing forces you to keep them. Of course, when you drop a commit, you'll always end up dropping all the commits that depended on it, and if you actually got somebody else to pull that commit you can't drop it from _their_ repository, but undoing things is not impossible. For example, let's say that you've made a mess of things: you've committed three commits "old->a->b->c", and you notice that "a" was broken, but you want to save "b" and "c". What you can do is # Create a branch "broken" that is the current code # for reference git branch broken # Reset the main branch to three parents back: this # effectively undoes the three top commits git reset HEAD^^^ git checkout -f # Check the result visually to make sure you know what's # going on gitk --all # Re-apply the two top ones from "broken" # # First "parent of broken" (aka b): git-diff-tree -p broken^ | git-apply --index git commit --reedit=broken^ # Then "top of broken" (aka c): git-diff-tree -p broken | git-apply --index git commit --reedit=broken and you've now re-applied (and possibly edited the comments) the two commits b/c, and commit "a" is basically gone (it still exists in the "broken" branch, of course). Finally, check out the end result again: # Look at the new commit history gitk --all to see that everything looks sensible. And then, you can just remove the broken branch if you decide you really don't want it: # remove 'broken' branch git branch -d broken # Prune old objects if you're really really sure git prune And yeah, I'm sure there are other ways of doing this. And as usual, the above is totally untested, and I just wrote it down in this email, so if I've done something wrong, you'll have to figure it out on your own ;) Linus - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html