PR Mirror

PR Mirror is a CLI tool to mirror an existing pull request from a public GitHub repository by:

1. Cloning the repo (via SSH),
2. Fetching the pull request as a local branch,
3. Creating a new branch based on it with an empty signed commit (to distinguish the mirror),
4. Pushing the branch to the same repo,
5. Opening a new pull request (via the GitHub CLI) from the mirrored branch into a specified base branch.

This is useful in scenarios like:

- Creating a filtered or internal mirror of external PRs
- Testing PRs against a different base branch (e.g., staging instead of main)

Prerequisites

Node.js (see package engines)

git (must be in PATH)

GitHub CLI (gh) installed and authenticated (via gh auth login)

Git commit signing configured (required). This tool uses git commit -S for the tracking commits.

SSH access to GitHub (git@github.com must be reachable)

Usage

``bash
prmirror [-b ] -n -o -r [-d] [-s] [-v]

Clean up mirror-repo directory and exit


prmirror -c
`

Installation

`bash
npm install -g @pandaswhocode/pr-mirror
`

Or run without installing:

`bash
npx @pandaswhocode/pr-mirror -n -b -o -r
`

$3

| Flag | Description |
| ----------------------- | ------------------------------------------------------------------------------------------------------------------------- |
| -b, --base | Base branch to target for the new PR (defaults to DEFAULT_BASE or main) |
| -c, --clean | Delete the mirror-repo directory and exit (no other arguments are needed) |
| -o, --org | GitHub organization (can use DEFAULT_ORG env var) |
| -r, --repo | GitHub repository name (can use DEFAULT_REPO env var) |
| -s, --sync | Sync the mirror-pr branch and update the mirror PR |
| -d, --deleteAfterAction | Delete the mirror-repo directory after a successful create/sync run (cleanup errors are logged but do not fail the run) |
| -h, --help | Show help |
| -n, --number | (Required) Pull request number to mirror |
| -v, --verify | Show resolved inputs and ask for confirmation before proceeding |

$3

You can set defaults in a .env file in your working directory:

- DEFAULT_ORG
- DEFAULT_REPO
- DEFAULT_BASE
- DEBUG (set to true for verbose logging)

Note: if DEFAULT_BASE is not set and --base is not provided, the base branch defaults to main.

Example (Create new mirror)

`bash
prmirror -n 42 -b main -o PandasWhoCode -r pr-mirror
`

To verify the resolved inputs before making any changes:

`bash
prmirror -n 42 -b main -o PandasWhoCode -r pr-mirror -v
`

This will:

- Clone git@github.com:PandasWhoCode/pr-mirror.git into a temporary mirror-repo directory
- Fetch pull request #42 into a temporary branch
- Create a new branch mirror/pr-42 from it
- Add an empty signed commit for traceability
- Push mirror/pr-42 to origin
- Open a new pull request targeting main, authored by your GitHub CLI user

$3

The new PR will be titled:

`text
chore:Mirror PR-42
`

And will include all commits from the original PR, along with an empty commit to mark it as mirrored.

Example (Sync existing mirror)

`bash
prmirror -n 42 -b main -o PandasWhoCode -r pr-mirror -s
`

This will:

- Clone git@github.com:PandasWhoCode/pr-mirror.git into a temporary mirror-repo directory
- Fetch pull request #42 into a temporary branch
- Sync the branch mirror/pr-42 from with the temporary branch
- Add an empty signed commit for traceability
- Push mirror/pr-42 to origin

$3

The existing mirror PR will be titled:

`text
chore: Mirror PR-42 (sync)
`

The PR will include all commits from the original PR, along with an empty commit to mark it as mirrored.

Example (Delete mirror-repo after success)

`bash
prmirror -n 42 -b main -o PandasWhoCode -r pr-mirror -d
`

Example (Clean mode)

This deletes the local mirror-repo directory and exits without doing any other work:

`bash
prmirror -c
`

Notes

The tool exports GITHUB_TOKEN and GITHUB_UNAME using the GitHub CLI so that gh pr create` can assign the author correctly.

The mirror-repo directory is created in the current working directory.

License

Apache 2.0