# rebase -p loses amended changes 2 messages from 2012-03-30 to 2012-03-30. Participants: J Robert Ray, Thomas Rast. Thread: https://gitlist.dev/t/30114 ## J Robert Ray, 2012-03-30 21:31 Subject: rebase -p loses amended changes Message-ID: URL: https://gitlist.dev/e/CADb3U%3D4DNt7Jnzq4eW-K%2BW1_sEfMgL6MxqY6qmPaJZagiFdmmg%40mail.gmail.com ``` I've found that 'rebase -p' can discard changes from a merge commit when it recreates the merge. If a merge is amended to add changes to a file unaffected by the merge, these changes are lost after a rebase. Attached is a script to demonstrate the problem. I've tested the script against git 1.7.9.5. I'll outline the steps starting from an empty repo. 1. Create a file (a) with some contents, then create three branches from this point, "mod-a," "mod-b," and "master-copy." 2. In "mod-a," modify a. 3. In "mod-b," create a different file (b). 4. Merge (--no-ff) "mod-a" onto master. 5. Amend the merge with a modification to a. 6. Merge (--no-ff) "mod-b" onto "master-copy." 7. Rebase -p master onto "master-copy." Notice the change to "a" from step #5 is now gone. "a" reverts to the pre-amended version after step #4. I assume this isn't expected behavior and is a bug. ``` ## Thomas Rast, 2012-03-30 22:49 Subject: Re: rebase -p loses amended changes Message-ID: <87ty15vh4c.fsf@thomas.inf.ethz.ch> URL: https://gitlist.dev/e/87ty15vh4c.fsf%40thomas.inf.ethz.ch In-Reply-To: ``` J Robert Ray writes: > If a merge is amended to add changes to a file unaffected by the > merge, these changes are lost after a rebase. Attached is a script to > demonstrate the problem. > 4. Merge (--no-ff) "mod-a" onto master. > > 5. Amend the merge with a modification to a. > 7. Rebase -p master onto "master-copy." > > Notice the change to "a" from step #5 is now gone. "a" reverts to the > pre-amended version after step #4. That's pretty much expected. rebase -p attempts to (conflicts will happen again) replay the merge. I don't think anybody's come up with a clear idea of how to apply the conflicted or evil parts of the merge mechanically. -- Thomas Rast trast@{inf,student}.ethz.ch ```