自分裂以来，Git合并成分支并同时更改

Question

Suppose I am on branch master and run git branch dev - this will create a new branch.

Then I make some changes to branch dev

Then I make some completely different changes to branch master , but some are to the same file

   master -> (arbitrary # of commits) -> master*
        \
         \___ dev -> (arbitrary # of commits) -> dev*

And now I run git merge

Changes made to dev will be added to master

Q1) Will changes made to master be overwritten?

Q2) What if the changes made to dev are to the same file as the changes made to master ?

Q2b) What if I want changes to one branch to take priority?

For example: test.js was changed on lines 2-7 in master but it was changed on lines 5-10 in dev .

What if I want the changes in master to take priority. That is, I want this merge to ignore all changes to test.js from dev

Answer 1

Git merge does exactly as it says. It'll merge your changes.

$ git checkout master $ git merge dev

This will merge all your changes from dev into master. Depending on the severity of the merge it'll create a separate merge commit (you'll have to step through that commit and write a commit message).

• If you modify the same line (or same critical sections) in both branches, you'll get a merge conflict ( git merge --abort if you start panicking).
• If you modify the same file, but not the same lines, it'll just merge the changes together

This is a great example for why a test suite is important. It's a fast way to see when merges have gone bad, because your tests might fail on bad merges.

The documentation for git merge has great examples, too.