If it's part of the rebase. If commit 3 in the chain doesn't compile and half the tests fail, that's not very useful for someone trying to figure out how an ancient bug nobody noticed for a year got into the code. If commit 4 fixes it, then 3+4 -> 3.

But if you add a function in commit 2, then realize three hours later than you just need to call another function, I don't need to see the function arrive, get used, half the tests written, the whole thing be deleted, and then a couple commits that do it the easy way and only needs 3 tests added.

That fakeout will be in the code tree forever and each new dev who is trying to grok the code will see that the line of whitespace on line 35 came along with a function that doesn't exist anymore and only really ever did on David's machine.