Understanding and Resolving Merge Conflicts

Merge conflicts are a common occurrence when multiple people work on the same project using version control. They happen when Git can't automatically figure out how to combine changes from different branches because those changes overlap. Think of it like two people editing the same sentence in a document simultaneously without communicating – Git gets confused about which version to keep. The good news is that understanding and resolving them is a fundamental skill that becomes second nature with practice.

Why do merge conflicts happen?

Conflicts arise when:

• Two or more developers modify the same lines of code in the same file on different branches.
• One developer deletes a file that another developer has modified.

graph TD
    A[Main Branch] --> B{Feature Branch A}
    A --> C{Feature Branch B}
    B --> D(Merge Feature Branch A into Main)
    C --> E(Merge Feature Branch B into Main)
    D --> F{Conflict on Main}
    E --> F

When a merge conflict occurs, Git will stop the merge process and inform you. You'll see messages indicating which files have conflicted. At this point, Git presents you with the conflicted file, which will contain special markers to show you where the conflicting changes are located.

The lines marked with <<<<<<< HEAD, =======, and >>>>>>> [branch-name] are the conflict areas.

• <<<<<<< HEAD: Indicates the start of the changes from your current branch (the one you're merging INTO).
• =======: Separates the changes from the two branches.
• >>>>>>> [branch-name]: Indicates the end of the changes from the branch you are merging FROM.

Resolving a merge conflict involves manually editing the conflicted file. You need to:

1. Identify the conflict markers.
2. Decide which code to keep. This might mean:
   • Keeping only your changes.
   • Keeping only the incoming changes.
   • Combining parts of both.
   • Writing entirely new code to resolve the conflict.
3. Remove the conflict markers. (<<<<<<<, =======, >>>>>>>).