About branch protection rules
You can enforce certain workflows or requirements before a collaborator can push changes to a branch in your repository, including merging a pull request into the branch, by creating a branch protection rule.
By default, each branch protection rule disables force pushes to the matching branches and prevents the matching branches from being deleted. You can optionally disable these restrictions and enable additional branch protection settings.
By default, the restrictions of a branch protection rule don't apply to people with admin permissions to the repository. You can optionally choose to include administrators, too.
You can create a branch protection rule in a repository for a specific branch, all branches, or any branch that matches a name pattern you specify with fnmatch syntax. For example, to protect any branches containing the word release, you can create a branch rule for *release*. For more information about branch name patterns, see "Managing a branch protection rule."
You can configure a pull request to merge automatically when all merge requirements are met. For more information, see "Automatically merging a pull request."
About branch protection settings
For each branch protection rule, you can choose to enable or disable the following settings.
For more information on how to set up branch protection, see "Managing a branch protection rule."
Require pull request reviews before merging
Repository administrators can require that all pull requests receive a specific number of approving reviews before someone merges the pull request into a protected branch. You can require approving reviews from people with write permissions in the repository or from a designated code owner.
If you enable required reviews, collaborators can only push changes to a protected branch via a pull request that is approved by the required number of reviewers with write permissions.
If a person with admin permissions chooses the Request changes option in a review, then that person must approve the pull request before the pull request can be merged. If a reviewer who requests changes on a pull request isn't available, anyone with write permissions for the repository can dismiss the blocking review.
Even after all required reviewers have approved a pull request, collaborators cannot merge the pull request if there are other open pull requests that have a head branch pointing to the same commit with pending or rejected reviews. Someone with write permissions must approve or dismiss the blocking review on the other pull requests first.