I have a feature branch with many trial-and-error commits and I want to combine all my changes into a single commit before merging to develop. I'm using git rebase -i to do this but getting surprising results.
My feature branch is fully ahead of develop and develop is not ahead of my feature branch. As a pre-merge step, I created a new branch feature-squash from the develop branch, checked out my feature branch, and then ran git rebase -i feature-squash. In the editor screen, I left pick for the first commit but for every commit after it I chose to squash. Then I committed the rebase instructions.
The idea is that after this is done, the repo contents for feature-squash should be completely identical to the original feature branch, but only a single commit ahead of develop.
To my surprise there were multiple points during the rebase when merge conflicts were found. Each time I resolved the conflict in favor of "theirs" (choosing the alternative not on HEAD), git added the resolved files, and ran git rebase --continue. This happened multiple times, but not for every commit, only some of them.
I don't understand why there are merge conflicts in this situation, when all commits from develop had already been merged into my feature branch and are therefore in the branch history. What are my commits conflicting with? Is squash not the right choice for what I'm trying to do?