Git Branching, PRs, and Merges

Warmup

• What have you heard so far about branching in Git?
• Git is a Decentralized Version Control System (DCVS). What does decentralized mean in this context?
• What questions do you still have about Git/GitHub

Overview

• Creating a branch
• Checking out a branch
• Pushing a branch
• Submitting a pull request
• Checking out master
• Getting the latest version of master
• Adding code from master to a branch

Branches

• Check out a branch when you want to work on a new feature
• Keep your branch names snake case
• Branch names should describe the feature you plan on implementing
• Branch names can start with a number, but have a good reason

New Git Commands

$ git branch new_branch_name
$ git checkout new_branch_name (<= branch name should match)
$ git push origin branch_name
$ git merge master (<= merges master into current branch)

Checking out a New Branch

$ git branch new_feature
$ git checkout new_feature

Do work. Make commits.

Pull Requests

• Check to see that your code can be merged
• Ask a teammate to review code
• Ask a teammate to merge your changes to the master branch

Submitting a Pull Request

$ git push origin branch_name
$ hub browse

Submitting a Pull Request (continued)

On GitHub:

• Compare & pull request
• Review files
• Title
• Message
• Create pull request

Might result in merge conflict.

If There is a Merge Conflict

$ git checkout master
$ git pull origin master
$ git checkout branch_name
$ git merge master

Resolve merge conflict.

$ git push origin branch_name

Pull request will be updated with your fix.

Reviewing a Pull Request

• Review files
• Make comments
• Request changes

Note: You can pull down a branch to review by following these directions

Merging a Pull Request

• Review files (again!)
• Click Merge pull request
• Write message
• Click Confirm merge
• Click Delete branch

Pulling from Master

• Want to make sure you have most up to date master?

$ git checkout master $ git pull origin master

Merging from Master (Locally)

• If you are working on a branch and you want code in your branch that your teammate has pushed:

$ git status - Make sure you have everything committed $ git checkout master $ git pull origin master $ git checkout branch_with_my_feature $ git merge master

Might result in merge conflicts

Resolving Merge Conflicts

• $ git status will list the files that have conflicts
• Open each one
• Decide what to keep
• Remove tags indicating merge conflict

Summary

• How do you create a new branch in Git?
• How do you check out a new branch?
• How do you push that branch to GitHub?
• At a high level, how do you submit a pull request?
• How do you check out master?
• How do you get the latest version of master?
• What do you do if you want to add code from master to your branch?