Git provides 3 types of merging, Fast-Forward, Automatic and Manual. A manual merge is required when git is unable to resolve any conflicts , this results in a merge conflict.
Within this example we will generate a merge conflict and then manually resolve from within the command line.
File
First, lets look at the contents of the file will be generate a conflict on.
11:44:38-felix001~/projects/example (master)$ cat README.md xyz
New Branch/Amend File
Next we create a new branch and update the file.
11:44:52-felix001~/projects/example (master)$ git checkout -b create-conflict Switched to a new branch 'create-conflict' 11:45:24-felix001~/projects/example (create-conflict)$ sed -i 's/xyz/abc/g' README.md 11:45:46-felix001~/projects/example (create-conflict)$ git commit -am "bad update" [create-conflict f85beb1] bad update 1 files changed, 1 insertions(+), 1 deletions(-)
Master Branch/Amend File
We then switch back to the master branch. And change the same line within the file.
11:46:15-felix001~/projects/example (create-conflict)$ git checkout master Switched to branch 'master' 11:46:22-felix001~/projects/example (master)$ cat README.md xyz 11:46:35-felix001~/projects/example (master)$ sed -i 's/xyz/123/g' README.md 11:46:49-felix001~/projects/example (master)$ cat README.md 123 11:47:03-felix001~/projects/example (master)$ git commit -am "bad update" [master 231df4e] bad update 1 files changed, 1 insertions(+), 1 deletions(-)
Merge
Now when we try to merge our new branch with master, we will create a merge conflict. Merge conflicts must be resolved before we can continue.
11:47:43-felix001~/projects/example (master)$ git merge create-conflict Auto-merging README.md CONFLICT (content): Merge conflict in README.md Automatic merge failed; fix conflicts and then commit the result. 11:48:09-felix001~/projects/example (master|MERGING)$ git status # On branch master # Unmerged paths: # (use "git add/rm ..." as appropriate to mark resolution) # # both modified: README.md # no changes added to commit (use "git add" and/or "git commit -a")
If we now look at the README file you will see the following,
<<<<<<< HEAD abc ======= 123 >>>>>>> create-conflict
Resolve Conflict
Edit the file so only contains a single update, i.e so it just reads abc. We then commit and the merge conflict is successfully resolved.
11:51:30-felix001~/projects/example (master|MERGING)$ git commit -am "resolve" [master d5d1c9f] resolve 11:51:42-felix001~/projects/example (master)$ git status # On branch master nothing to commit (working directory clean)
Note : To rollback the merge you can run the command git merge –abort
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