GitHub Default Branch

Rename your default branch on GitHub easily. By default it renames master to main, but is configurable using the --new and --old flags.

If provided with an --org argument, it will run on all repositories within that organisation. Alternatively, you can provide a --repo argument to edit a single repo.

For each repo, this tool will:

• Create a new branch at the same commit SHA as the old one
• Update all open pull requests to point at the new branch
• Update the default branch for the repo
• Delete the old branch
• Update known URL patterns in source files
• Update any branch protections for $old to $new. (This does not work with patterns, it has to be an exact match)

Installation

npm install -g github-default-branch

Development

git clone https://github.com/mheap/github-default-branch.git
cd github-default-branch
npm ci

Authentication

Create a personal access token with the repo scope. This is the value for <token> in the examples.

If you don't want your token to be stored in your shell history, you can set GITHUB_TOKEN in the environment and that will be read instead

Usage

# Rename master to main
github-default-branch --pat <token> --repo user/repo

# Rename dev to develop
github-default-branch --pat <token> --repo user/repo --old dev --new develop

# Rename all repos owned by an org
github-default-branch --pat <token> --org my-org-name

# Rename all repos owned by a user
github-default-branch --pat <token> --user my-user

Run with the --verbose flag to see debug information

Options

Flag	Description	Default
--pat	GitHub API Token	N/A
--repo	The repo to update (format: user/repo)	N/A
--user	Update all repos owned by the provided user (example: my-user)	N/A
--org	Update all repos in the provided org (example: my-org-name)	N/A
--team	Update all repos in the provided team (example: my-team-name), only usable in combination with org parameter	N/A
--keep-old	Keep the old branch rather than deleting it	false
--dry-run	Output log messages only. Do not make any changes	false
--list-repos-only	List repos that would be affected, then exit	false
--skip-forks	Skips forked repositories	false
--skip-update-branch-protection	Skip updating branch protections	false
--old	The name of the branch to rename	master
--new	The new branch name	main
--confirm	Run without prompting for confirmation	false

Replacements

Part of this script checks for the existence of files and updates their contents. Replacements are the mechanism for these updates.

How it Works

Each .js file in the src/replacements folder is given a chance to run during the content updating step of the script. Each file in src/replacements is expected to export a function, that function receives all of the options that are available to the outmost script.

If there is nothing to replace, then the script moves on to the next replacement.

How to Add a Replacement

Add a file to src/replacements with a .js extension

Like this:

module.exports = function ({
  owner, // string - repo owner
  repo, // string - repo name
  old, // string - old branch name
  target, // string - new branch name
  octokit, // Octokit - oktokit instance
  verbose, // boolean - verbose flag
  isDryRun, // boolean - dry run flag
}) {
  // code goes here
  return {
    path: "<path to file in repo>",
    replacements: [
      {
        from: "<from pattern>",
        to: "<to pattern>",
      },
      {
        from: "<from pattern>",
        to: "<to pattern>",
      },
    ],
  };
};

The file with the path in your repo will have any line matching from be swapped out with to

Known Issues

The replacement system gives you octokit, that's great! Unfortunately replacement functions do not currently support asynchronous calls, that's bad.