Code review has become one of the most important (and used) techniques when it comes to code quality. The code review process may have very different workflows and subtleties, but it is often driven around the following steps: The developer responsible by the code (a new feature, a bug fix, a refactor, etc) sends his changes to other colleagues (in git it is called a patch, that can be transformed into a pull request, merge request, or any other name your Git repository hosting service calls ...
