prepare-pr-diff-worktree

name: prepare-pr-diff-worktree description: Use when given a GitHub pull request link and needing to create an isolated worktree, check out PR code, export the PR diff to .diff, and return JSON metadata (code_path, diff_filename, work_tree) even when gh authentication is unavailable or the current directory is outside the target repo.

Prepare PR Diff Worktree

Overview

Create a new git worktree from a target project, check out the target PR in that worktree, save the PR diff as <pr-number>.diff, and emit one JSON object for later steps.

Use the bundled script for deterministic execution.

Input

• Required: pr_link
  • full PR URL, for example https://github.com/pingcap/tidb/pull/12345
  • or PR number, for example 12345
• Optional: project_path
  • absolute path to the target project git repository
  • required when current directory is not inside that project

Output Contract

Print exactly one JSON object with these fields:

• code_path: absolute path to the newly created worktree
• diff_filename: generated diff filename, always <pr-number>.diff
• work_tree: worktree name (folder name under worktrees/)

Example:

{"code_path":"/abs/repo/worktrees/pr-12345","diff_filename":"12345.diff","work_tree":"pr-12345"}

Command

If currently inside the target project:

./prepare-pr-diff-worktree/scripts/create_pr_worktree_and_diff.sh <pr_link>

If currently outside the target project:

./prepare-pr-diff-worktree/scripts/create_pr_worktree_and_diff.sh --project-path <project_path> <pr_link>

Authentication Modes

• Preferred mode: authenticated gh (gh auth login)
  • checks out with gh pr checkout
  • exports diff with gh pr diff
• Fallback mode (no gh auth):
  • fetches PR head with git fetch https://github.com/<owner>/<repo>.git pull/<pr-number>/head
  • checks out detached FETCH_HEAD
  • downloads diff from https://github.com/<owner>/<repo>/pull/<pr-number>.diff

Workflow Implemented by Script

1. Resolve the target git repository from current directory or --project-path.
2. Resolve PR number and owner/repo from PR URL, PR number, and origin remote.
3. Create a unique worktree under <repo-root>/worktrees/.
4. Check out PR code (preferred gh, fallback git fetch for public GitHub PRs).
5. Write <pr-number>.diff at the worktree root (preferred gh, fallback curl from .diff URL).
6. Print the output JSON object.

Notes

• This workflow assumes GitHub PRs.
• If using PR number input, origin should point to the target GitHub repo.
• Unauthenticated fallback works for public PRs; private PRs still require valid auth.
• If worktrees/pr-<number> already exists, the script appends a numeric suffix to create a unique work_tree.