Git Katas

Notes:

You should never use push --force or equivalent unless otherwise stated

You should try and perform all the tasks listed here using the command line first, and relying on a GUI later.

Task 1 - Create a new empy repo

$ cd
$ mkdir repos
$ cd repos
$ mkdir kata
$ cd kata
$ git init
$ # create a file named 'hello.txt' containing "Hello, worldd"
$ git add hello.txt
$ git commit -m "Initial commit"

It's possible git will ask you to configure your name and email before allowing you to commit - if so, do what it says by running git config with the correct arguments.

Then verify using git log that you did create a commit

Task 2 - Clone this repo

The first task is to clone this repo in a place where you have write access.

You can either fork it on GitHub, or re-create it from scratch on GitLab for instance.

Task 3 - Simple commit

Edit a file in this repo
Make a change
Make sure the changed are saved
Use the command git status the assert the presence of the change
Add the file with git add <file>
Make a commit with git commit -m "<message>"

Task 4 - git log, git blame

There's a typo in the file numbers.txt - find the name and email of the dev who is responsible for this !

Task 5 - The cycle of collaboration

Goal: learn how to share a branch across the same team

Make sure Alice and Bob both have cloned the repo

Alice: add your name to the THANKS
Alice: make a commit with the message "Add Alice to THANKS file"
Alice: push the commit to the main branch
Bob: get Alice's changes from the main branch (using fetch and merge for instance)
Bob: make a commit with the message "Add Bob to THANKS file"
Bob: push the commit to the main branch
Alice: update the main branch

Alice should end up with a log looking like this:

* 6430036 - Add Bob to THANKS file (62 seconds ago) <bob>
--- a/THANKS
+++ b/THANKS
@@ -1 +1,2 @@
 Alice
+Bob

* a6c829f - Add Alice to THANKS file (2 minutes ago) <alice>
-
+Alice

Task 6 - Two commits from one file

Goal: learn about the git index

This should be done by each member of the team.

Change at least two different lines in index.html file (I'm sure you can find something to improve)
Make two commits, each one containing a different line change.

Task 7 - Undoing changes

Goal: learn about the various ways to undo changes in git

This should be done by each member of the team.

Revert the two commits made during task 2
Change a few lines in index.html and then restore the file to its original version
Move the head of the branch to where it was before task 2 started branch

Task 8 - Happy merge

Goal: show how to merge in the trivial case

Alice: Change the <title> in index.html
Alice: push the changes to the main branch
Bob: do not fetch Alice's changes
Bob: change something in the JavaScript code
Bob: make a commit and try to push it to the main branch - git will ask your to merge first
Bob: merge your branch and push the result

Task 9 - Happy rebase

Some as the previous one, but use rebase so that there is no merge commit in the history.

Task 10 - Conflict resolution

Goal: learn about merging conflicting changes

Alice: Edit 'conflict.txt' and add the following text on line 2:

C'est la goutte d'eau qui met le feu aux poudres

Alice: make a commit and push it to the main branch
Bob: make sure to not fetch Alice's changes at this point.
Bob: Edit 'conflict.txt' and add the following line also on line 2:

C'est l'étincelle qui fait déborder le vase

Bob: make a commit and try to push it to the main branch - git will ask your to merge first
Bob: try and merge - git will tell you that there are conflicts
Alice & Bob: resolve the conflict and push the resolution

Task 11 - Code review using a feature branch

Alice: Add some code in 'index.html'
Alice: Make sure to include a small mistake in the code you added
Alice: Make a commit and push it in a branch named 'feature/stuff'
Alice: Create a merge request (GitLab) or a pull request (GitHub)
Bob: look at Alice's changes and leave some comments about the typo
Alice: Use rebase or git commit --amend to address Bob's feedback and fix the typo (you are allowed to use push --force this time)
Bob: Merge Alice's branch

Task 12 - Interactive rebase

Switch to the dev branch.

Verify that there are 5 commits between main and dev (most recent last):

* Add transaction parser
* Refactor old code
* Compute transaction price
* Fix issue on parser
* Compute transaction price: add test

Use an interactive rebase of dev on top of main so that the history looks like this:

* Refactor old code
* Add transaction parser
* Compute transaction price

Hints:

You can do it in several passes
You can create a tag to verify your rebase does presevre all the changes

Task 13 - Cherry-picking

If you look at the repo, you will see that the 'release' branch does not contain the commit that bumps the year in the COPYRIGHT file (which is expected since it was created in 2021).

Use git diff to confirm this.

Then use cherry-picking to fix the COPYRIGHT year on the release branch as well

Finally, create an push a v1.1 tag on the release branch

x0rld/kata-git