Review

Collaboration Overview

Centralized Workflow

Branches

Your machine

fork

Your copy

Starter repo

git clone

git add *

Edit files

Staging area

git commit -m ".."

git push

Create local repo: git clone

Check for updates: git fetch

Integrate updates: git pull

Let's do a quick demo

Facilitate collaboration

Work on the same documents at the same time

Manage conflicts

Assign tasks to group members

Only one remote repsository

Don't fork! (only clone)

Remote (GitHub) is truth

One (of many) workflow structures

Provide tools for assigning and tracking tasks

Awesome for planning projects

Facilitate communication

Documentation

You can close issues via a commit message!

Do this throughout today's exercise

Documentation

# Close issue number 7
git commit -m "Added a new file.  Close #7"

Person 1: edit Readme.md

Person 2: create assignment.r (with some code/text in it)

Each person should add and commit as usual (and close the corresponding issues!)

Person 1 should push their changes to GitHub

clone

clone

commit

commit

push

commit

push

push

pull --rebase

Git gave us an error (luckily), preventing us from overwriting the truth (remote)

The --rebase option pulls down code, and integrates your changes with the changes on the remote

Achieves this by rewinding your code to a common ancestor, and the applying changes on top of it

Rebase documentation

Person 3: Write your favorite candy in  Readme.md

Person 4: Write your favorite candy in Readme.md

Person 3: Add, commit, push

Person 4: Add, commit, push, rebase.....

Arises when the same part of a file differs across commits

Must be resolved manually

Common part of the process

Multiple ways to resolve conflict

You tried to pull --rebase to to integrates changes

But you got an error

Git has initiated a rebase:

# Put local commits on top of changes to the remote
git pull --rebase

Auto-merging your-file-name.r
CONFLICT (content): Merge conflict in your-file-name.r

# What is happening
git status

but how?

open up the file with a conflict

Pull in remote changes

Manually resolve conflict in the file

Run git add to add changes to the rebase

Continue with the rebase (no need to commit)

# Put your changes on top of the remote changes
git pull --rebase

<<<<<<< HEAD  # delete this non-sense!
# Keep relevant comments and code
x <- 7

# Add any/all edited files
git add .

# Continue through rebase, then push changes to GitHub
git rebase --continue
git push origin master

master

new-idea

# Create a new branch of the current commit
git branch new-idea

# Start working on the branch by checking it out
git checkout new-idea

# You can do those in one line, if you prefer
git checkout -b new-idea

Create a new branch called "super-hungry"

Checkout your new branch

Edit the Readme.md to have your favorite snack when you're super hungry

Add and commit those changes

# Label the current commit as a new branch super-hungry
git branch super-hungry

# Checkout (i.e., start working in) your super-hungry branch
git checkout super-hungry

# Add and commit changes as usual
git add .
git commit -m "Added super-hungry snacks"

Switch back to your master branch

Change your favorite snack in Readme.md to another snack

Merge your super-hungry branch into your master branch

# Checkout (i.e., switch to working in) your master branch
git checkout master

Add and commit those changes

# Add and commit changes as usual
git add .
git commit -m "Changed my favorite snack"

# Merge super-hungry branch into master (current) branch
git merge super-hungry

Just like resolving conflicts for a rebase: edit & save files

Once you merge, you'll have to add and commit

<<<<<<< HEAD

# This is the code section in your local version
# It can be multiple lines
x <- 6

======= # This is the divider between local and remote code

# This is the code section in your REMOTE version
# It can be multiple lines
x <- 7

>>>>>>> remote-branch-name-or-hash

# Add and commit changes as usual
git add .
git commit -m "Changed my favorite snack"

All together:

# Make and checkout new branch
git checkout -b super-hungry

# Make some changes to your file, then add and commit
git add .
git commit -m "Added super-hungry fav. food"

# Switch back to master branch
git checkout master

# Make some changes, then add and commit
git add .
git commit -m "Made changes to master"

# Merge in changes from super-hungry branch
git merge super-hungry

# Resolve the conflict MANUALLY in the file, then add and commit
git add .
git commit -m "Merged in super-hungry branch"

Centralized Workflow (atlassian) 

Resolving merge conflicts (GitHub)

Using branches (atlassian)

Closing issues via a commit (GitHub)

Merging v.s. rebasing (atlassian)

Branches in a nutshell (git)

Merge v.s. rebase (stackoverflow)

Assignment-7: Collaborative coding (due Wed. 2/24).  Turned in by 1 person, worth 50 points

Final Project: Proposal(due Wed. 2/24).  Turned in by 1 person, worth 50 points

Data resources