Git Branch Merging: Differences Between Fast-forward and Regular Merge, and Operation Methods

### Overview of Git Branch Merging Merging branches is a critical operation for integrating code in team collaboration, used to consolidate development results (e.g., functional modules) from different branches into the main project (typically the `master` branch). Git provides two merging methods: **Fast-forward Merge**: When the main branch (e.g., `master`) has no new commits, the history of the merged branch extends linearly with the main branch. Git directly advances the main branch pointer without creating a new commit. This method is simple, conflict-free, and suitable for merging after independent development. **Regular Merge**: If both the main branch and the feature branch have new commits (i.e., a diverged history), Git creates a new merge commit during merging to integrate modifications from both branches. Manual resolution is required if there are conflicts in the same file. This method is suitable for merging after parallel development and clearly preserves the branch divergence history. Both methods are implemented via `git merge [branch-name]`, and Git automatically determines the merge type based on branch history. Fast-forward is ideal for simple scenarios, while regular merge is a practical solution for handling parallel development, ensuring clear branch divergence records.