tobiasb / git-lunch-n-learn

Resources for Git lunch n learns

Git Lunch-n-Learn Cheat Sheet

Prerequisites

Clone this repo

git clone [e-mail]:tobiasb/git-lunch-n-learn.git
cd git-lunch-n-learn

Clone sample repos

./clone-sample-repositories.sh

Committing

• A commit has an ID, knows about its parent commit(s), author, etc.
• Forms a linked list
• Create commit message in the format: "When applied, this commit will <commit message>"

Demo:

cd secret-santa-sms-a

subl secret_santa_generator.py
< remove extra whitespace >
git status
git add secret_santa_generator.py
git status
git commit -m "Fix witespace"
git status
git push
< show tree in GUI >

Lifecycle of a local change

(source: https://git-scm.com/book/en/v2/Git-Basics-Recording-Changes-to-the-Repository)

Branching

• Pointer to a commit
• Remote vs. Local

Demo:

git branch improve-tests
git checkout improve-tests

git apply ../../patches/patch00a.diff && git commit -am "Add test case"
git apply ../../patches/patch00b.diff && git commit -am "Update pytest version"

< commit changes using GUI using partial staging >

git push --set-upstream origin improve-tests

Merging

• Fast-forward vs. merge commit

Demo:

git checkout master

git merge improve-tests
git reset origin/master --hard
git merge improve-tests --no-ff

git push

Resetting

• Hard vs. Soft
• Reference commit, branch, tag

Demo:

git branch my-branch

git reset version-1.0
git reset master --hard
git reset 26a6c1b3e259dad24ec43a46baf2a519164c6a3f

Tags

• More pointers
• Reference hash, branch name, tag name

Demo:

git tag <tag name>
git tag <tag name> <commit hash>
git tag <tag name> <branch name>
git push --tags

Rebasing

Demo:

git checkout master
git pull 

git branch my-branch
git checkout my-branch
git push --set-upstream origin my-branch

git checkout master
git apply ../../patches/patch01.diff && git commit -am "Improve file handling" && git push

git checkout my-branch
git apply ../../patches/patch02.diff && git commit -am "Update Twilio package"
git apply ../../patches/patch03.diff && git commit -am "Improve documentation"
git apply ../../patches/patch04.diff && git commit -am "Update to correct Twilio package"
git push

< show my-branch relative to master in GUI >

git rebase master

<show what "git push" and "git status" would say >

git push -f

Stashing

Based on result of Rebasing

• git stash is a stack of backed up changes

Demo:

< edit test_secret_santa_generator.py >
git checkout master

git stash
git stash pop

Squashing

Based on result of Rebasing

Demo:

git rebase master -i
git push -f

Resolving Conflicts

Demo:

git checkout master
git apply ../../patches/patch05.diff && git commit -am "Make tests even better"
git push

git checkout my-branch
git rebase master

< open conflict in pycharm -> right click -> Git -> Resolve Conflicts... -> Merge >

git add test_secret_santa_generator.py
git rebase --continue

• Show aborting a rebase git rebase --abort

Ignoring files/directories

• Add files/directories that should not be commited to .gitignore

Demo:

echo "super secret password" > credentials.txt
git status
vi .gitignore
git status

Tooling

• Try to master the command line
• Use the GUI

Cherry picking

Resetting local repo

./cleanup-sample-repositories.sh

Future topics

• Remotes
• Configuration
• Hooks
• Submodules