GitHub CODEOWNERS: What Every Developer Should Know

GitHub's CODEOWNERS feature allows developers to specify users or teams responsible for certain files in a repository, but misconfigurations can lead to unexpected behavior. This blog post explores various scenarios and their results when using the "Require review from Code Owners" branch protection policy setting. Some key points include: 1. An empty CODEOWNERS file allows any approval by any non-author user with Write permission to merge code into a protected branch, regardless of the "Require review from Code Owners" setting. 2. A misconfigured Team in CODEOWNERS can block merging even if an approver has Write access directly. 3. If a user is assigned as a code owner but does not have effective Write permission, their approval will still count towards the required check to merge code into a protected branch. 4. Assigning Teams instead of users in CODEOWNERS files can prevent misconfigurations when reviewers leave the organization. 5. Using Arnica's solution can help identify and fix misconfigured CODEOWNERS across all organizations for free, regardless of the number of users and repositories scanned.