Why does git rebase --onto over here only pick up 2 commits instead of 5?-CodePudding

I'm solving exercises over here:

We need to add commits H and I to your-master.

This is supposed to be the solution:

git rebase --onto your-master issue-555 rebase-complex

We're basically telling git to pick up all commits between issue-555 and rebase-complex branches and place them into your-master, isn't it?

Then this should have picked up G, F, E, H, and I in that order and placed them on top of D.

Why does this solution only pick up H and I but ignores E, F, and G?

CodePudding user response：

We're basically telling git to pick up all commits between issue-555 and rebase-complex branches and place them into your-master, isn't it?

No, we're telling Git to pick up all commits

that are reachable from rebase-complex
except those that are reachable from issue-555.

Keep in mind that a commit is "reachable" only by walking in the direction of the arrows in your graph, not in the opposite direction.

You can think of it as a set operation:

Take the set {A, B, E, H, I}
and subtract from it the set {A, B, E, F, G}.

CodePudding user response：

pick up all commits between issue-555 and rebase-complex branches

No. There are no commits "between" those two things.

A commit is just the name of one commit. It happens that issue-555 is G, and rebase-complex is I. There is nothing "between" those.

Also rebasing does not move or "pick up" any commits. You cannot move a commit or alter a commit in any way. Rebasing copies commits.

Now think about reachability thru the parent chain. The expression issue-555 rebase-complex means: Work your way back along the parent chain starting at I until you come to a commit whose parent is also reachable from G. Those are the commits to copy.

Well, that's H, because its parent E is reachable from G. So we copy everything from H thru I.