Welcome to the wonderful world of GIT :)!

Leave here with a better understanding of some advanced git commands &quickly fix mistakes

Today's GOAL:

Class Overview:

Commits, Log, Stashing & Merge

Amend + Rebase + Autosquash

Fixing Mistakes

Commits, log, stashing & merge

Commits

A COMMIT is a code snapshot, for how the project looked like at that point in time.

git commit -am 'Your Commit Message', it commits and adds to staging areas in the same time ( git add -A + git commit)
git commit --amend -m 'update your last commit message', change the text for your last commit

Not everyone will need a git log all the time but when you need it just remember:

3. git log --oneline --decorate --graph --all, prints the history of your commits showing where your branch pointers are and how your history diverged.

LEARN MORE

Stashing - Git Stash

Saves un-committed work, the stash is pretty safe from most disruptive git operations

Git Stash Operations

git stash stash changes
git stash list list changes
git stash show stash@{0} show the contents
git stash apply apply the last stash
git stash apply stash@{0} apply a specific stash

Advanced Stashing Operations

git stash --all keep all files
git stash --include-untracked keep untracked files
git stash save "WIP: making progress" name stashes
git stash branch <optional stash name> start a new branch from a stash
git checkout <stash name> --file grab a single file from stash

Even More Advanced Stashing Operations

git stash drop removes the last stash
git stash drop stash@{n} removes the nth stash
git stash clear removes all stashes

Merge, Fast Forward & Continuous Integration

Under the hood , merge commits are just commits The merge commit is just a marker of when a new feature was merged into master.

What is merge anyway?

Example Merge

Every once in a while you checkout master. You merge in your feature branch. And if there haven't been any additional changes to master, git will show you this message saying that it has fast forwarded.

What is Fast Forward?

Example Fast Forward

Text

Happens when you attempt to merge, but files have diverged

Merge Conflicts

Git stops until conflicts are resolved

Git ReReRe - REuse REcord REsolution

git saves how you resolve a conflict

Useful for:

long lived feature branch(like a refactor)

Next conflict: records & reuse the same resolution

rebasing

How do you use it?

Turn it on:

git config rerere.enabled true

use --global flag to enable for all projects

Example ReReRe

Merging smaller commits frequently, instead of waiting until a project is "done" and doing one big merge.

Continuous Integration

This means that features can be released quickly

CI works well when there are tests that ensure that new commits didn't "break the build"

It's even possible to perform a deployment at the end of a CI build!

Continuous Integration

Amend, Rebase & Autosquash

Amend a commit

Amend is a quick and easy shortcut that lets you make changes to the previous commit.

Commits can't be Edited!

Remember commits can't be edited!

A commit is referenced by the SHA

Even if it's the same author, the date is not!

Thus a new commit is created.

Rebase

What is Rebase anyway?

Imagine your branch and master branch have diverged
We can pull in all the latest changes from master, and apply our commits on top of them by changing the parent commit of our commits.

Rebase = give a commit a new parent

Merge vs Rebase

Power of Rebasing - Replay commits

Commits can be edited, removed, combined, re-ordered and inserted
Before they're "replayed" on top of the new HEAD

Interactive Rebase(rebase -i)

Interactive rebase opens an editor with a list of "todos"
- git will pick the commits in the specified order or stop to take action when editing or a conflict occurs
interactive rebase with a shortcut:

git rebase -i <commit_to_fix>^ (^ specifies the commit)

Rebase options I

pick, keep this commit
reword, keep this commit, just change the message
edit, keep this commit, but stop to edit more than the message
squash, combine this commit with the previous one and stop to edit the message.

Rebase options II

fixup, combine this commit with the previous one and keep the previous commit message.
drop, remove the commit(if you remove this line, the commit will be dropped to)