Git 在将要合并的同一分支的手动更新/提交之上自动合并

Question

I have a branch A which i want to merge with branch B (updated), there have been some code/files commit to branch A manually from branch B . Now i want to auto merge complete chages from branch B to A. I have below queries/doubts on this -

1. When i tried to do automatic merge, git shows new code/files addition/update which are already present in branch A as part of manual update/commit previously done.
2. Is it fine if go ahead and merge them, would there be code/file duplicacy?
3. Or should i be doing manual merge? but there are lots of changes

Give me chance to explain more if its not clear. Any help would be appreciated.

Answer 1

This is probably going to end up fine, and Git will not produce duplicate code.

When you do a merge, Git looks at the two heads (the branches you're merging), plus the merge base, which is usually the most recent common commmit. If both heads have the exact same contents for a file, then the merge is trivial, and Git picks that result. If they don't, it tries to incorporate the changes from each side.

When it does this, if the changes are to two separate areas of code, the merge succeeds, because Git will include the change from each side. If the changes are to the same area, but they're identical changes, then Git just takes that identical piece (once) and uses it in the result. If you have different changes to the same area, then Git will conflict and you'll have to resolve things manually.

If the merge succeeds without conflicts, then Git will probably have done the right thing and you'll get a sane result, although sometimes merges do result in odd behavior because Git only operates on lines and doesn't intrinsically know about the structure of your code. Usually you can detect this by building and testing your code, and in typical practice, unexpected behavior happens very rarely. Git doesn't duplicate code if both sides have similar changes; at worst, it conflicts and lets you figure out what to do.

If the merge has conflicts, you'll have to resolve them by hand. If you're doing the merge through GitHub using a pull request, it will tell you if there are conflicts or not in the pull request. If you're doing them on the command line, then you just have to try and see how it works out.