Using Git to contribute to Drupal

Cloning a module's project Git repository

How to get/update a local copy of the Git repository for a contributed module, theme, or distribution

Using Tugboat previews on Drupal Core and contrib merge requests

Drupal.org core and contrib issues now have a built-in live deployment preview feature, to easily allow testing of merge requests.

Merge request guidelines

General guidelines for merge requests, including scope, standards & testing

Working with patches

How to work with patches on Drupal.org.

• Applying a patch in a feature branch
• Making a patch
• Creating an interdiff
• Rerolling patches
• Command-only full patch workflow

Setting proper file permissions before committing files

File read/write/execute permissions to use for Drupal project files

Making maintainer-friendly "git am" single and multi-patches

How to make patches that include committer information and/or multiple commits

Using git blame

How to use Git's blame command to determine when a change was made

Using a Sandbox project to collaborate

How to use a Sandbox project on drupal.org as a means for a group to collaborate on a major software change