解决这个问题的偷懒方式: 手动编辑分支中已经在目标分支中的文件，使用从目标分支的文件复制的相同代码，并保存它。它被提交。现在，PR将自动更新您所做的新提交，从而解决问题。

这发生在GitHub中，当你压缩从目标分支合并的提交时。

I had been using squash and merge with Github as the default merge strategy, including merges from the target branch. This introduces a new commit and GitHub doesn't recognize that this squashed commit is the same as the ones already in master (but with different hashes). Git handles it properly but you see all the changes again in GitHub, making it annoying to review. The solution is to do a regular merge of these pulled in upstream commits instead of a squash and merge. When you want to merge in another branch into yours as a dependency, git merge --squash and revert that single commit before pulling from master once that other branch has actually made it to master.

编辑:另一种解决方案是重新基底和强制推。干净但被改写的历史

使用git的精选

如果重基过程对您来说像对我一样混乱，另一个选择是使用git精选。以下是步骤:

Update your local target branch using git pull. checkout the branch where you made changes and copy the commit IDs of the commits you want. if the branch name is tangled, do git checkout tangled and then git log. You can scroll through the git log output using the up/down arrows on the keyboard. The commit IDs are the long numbers that each commit contains. Create a new branch from your target branch (e.g main) using git checkout -b new-branch-name when you are on the target branch. On the new branch, do git cherry-pick commit-id where commit-id is the long number that you copied from git log which identifies the commit you want to push. You can do this multiple times, changing the id each time to get another commit. If you run git log on this new branch which you created, you can see that only the changes you have added exist after your target branch's head, as expected. Lastly, push the changes to remote using git push origin new-branch-name and create a pull request.

解决这个问题的一种方法是git在PR中rebase targetbranch。然后git push -force targetbranch，然后Github会显示正确的提交和diff。如果你不知道你在做什么，请小心使用这个。也许先签出一个测试分支来做rebase，然后git diff targetbranch以确保它仍然是你想要的。

对于遇到这种情况并对GitHub Pull Request行为感到困惑的其他人来说，根本原因是PR是源分支尖端与源分支和目标分支的共同祖先之间的差异。因此，它将显示源分支上直到公共祖先的所有更改，而不会考虑目标分支上可能发生的任何更改。

更多信息请访问:https://developer.atlassian.com/blog/2015/01/a-better-pull-request/

基于共同祖先的差异似乎很危险。我希望GitHub能够提供一个更标准的基于3方合并的PR。

编辑-我从来没有提到我总是使用明显的变通办法来避免由此产生的任何问题。只要定期将你的目标分支合并到你的PR分支中，你就不会遇到任何令人不快的意外。

如果你太担心会把事情搞砸，可以采用故障安全方法: 转到文件并手动删除更改，然后使用最后一次提交压缩

git add .  && git commit -a --allow-empty-message -m '' && git reset --soft HEAD~2 &&
git commit --edit -m"$(git log --format=%B --reverse HEAD..HEAD@{1})"

我没有矛盾，你就好走了!