Tom Ellis Tom Ellis -4 years ago 52
Git Question

Is merge without conflicts equivalent to rebase without conflicts?

Is it correct that a

git merge
will succeed with no conflicts if and only if the corresponding
git rebase
will succeed with no conflicts?

Answer Source

No, and in fact there's a trivial case where merge works fine but rebase doesn't:

...--o--A   <-- mainline
      \
       B--C--!C   <-- branch

where C is a commit that conflicts with A, and !C is its reversion. Merging branch back into mainline is equivalent in source-tree effect to merging commit B back into mainline, while rebasing copies both C (which conflicts with A) and then !C (which when being resolved, also conflicts with A).

Of course, you can rebase interactively and simply drop both C and !C in this case, but in more complex chains, you can see how a commit might conflict with A but a subsequent commit might effectively resolve that conflict "in advance", so that merging the tip of the branch back into the mainline has no conflicts.

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