Git like a pro

This repository contains a series of labs to be used in the workshop with the same name. This workshop aims to teach the use of some 'advanced' git commands and techniques, and also to increase the students understanding of the git internals.

The different labs are structured in different branches of this repository, you will have to switch from one branch to another in order to complete them.

Prerequisites

The only lab that really have some prerequisites is bisect-run. In order to be able to complete this lab, you will need the following:

• PHP >= 5.3 installed on your computer.
• Composer (PHP's package manager) installed globally or its phar file downloaded.
• It would be nice if you could checkout bisect-run branch, and install its dependencies by running composer install. This way we will save time at workshop's lab time. It doesn't matter if you then prefer to remove all non-versioned contents in the repo, this way composer has cached the required dependencies and it will take them from local cache on future installations.

Labs instructions

Rebase

Execute a rebase operation without facing any conflict:

• Checkout rebase-no-conflicts branch.
• Rebase it onto rebase-base branch.
• Tip: git log rebase-base…rebase-no-conflicts (show divergent commits).

Execute a rebase operation that results in conflicts you will have to solve:

• Checkout rebase-with-conflicts branch.
• Rebase it onto rebase-base branch.
• Resolve arising conflicts and finish the rebase operation.

Interactive rebase

Execute an interactive rebase operation:

• Checkout rebase-base branch.
• You can get its origin commit with git merge-base master head.
• Do some experimentation: join commits, edit, reorder...
• Finish the rebase operation and check the results.

Squash and fixup

Exercise git commit --squash and --fixup options:

• Checkout rebase-base branch.
• Add a new commit with --squash option, selecting as the squash target some old commit (not the last one).
• Repeat the previous operation but with --fixup option.
• Execute an interactive rebase with --autosquash option.
• Check the git log after finishing the rebase operation to check the results.

Rerere

Exercise git rerere command/feature:

• Run git config rerere.enabled 1.
• Checkout rerere-with-conflicts branch.
• Run a rebase onto rerere-base.
• Solve the arising conflicts and finish the rebase operation.
• Undo the rebase: git reset --hard ORIG_HEAD.
• Run the rebase again and see what happens.

Bisect

Make use of git bisect command to find the commit which introduced a bug:

• Checkout bisect branch.
• File.txt contains several lines with the text “EDD rocks!”, each one added by a different commit, but one line contains a typo: “EED” instead of ”EDD”.
• Make use of git bisect to identify the commit which introduced the line with a typo.
• Tip: use the commad grep EED file.txt to check if the commit is wrong.

Bisect with run subcommand

Make use of git bisect with the run subcommand to find the commit which introduced a bug:

• Checkout bisect-run branch.
• You need to make sure your computer meets the prerequisites (see section at the top of this document) to follow this lab.
• The current branch’s test suite has a failing test, and you have to find the commit which introduced it.
• Make use of git bisect run to find the commit which introduced the error.
• Tip: use vendor/bin/phpunit as the script for bisect run command.