Convert bare PR numbers in CHANGELOG.md to linkable GitHub PR links.

add_pr_links.py

#!/usr/bin/env python3
"""
Script to convert bare PR numbers in CHANGELOG.md to linkable GitHub PR links.

This script:
- Finds all PR numbers in the format (#1234) or (#1234, #5678, #9012)
- Converts them to linkable GitHub PR links: [#1234](https://github.com/owner/repo/pull/1234)
- Preserves already-linked PR numbers (won't double-link)
- Handles multiple PR numbers per line correctly
- Supports configurable GitHub repository

Usage:
    python3 add_pr_links.py --repo <repo_url> --file <filename>
    
Repository must be specified as full GitHub URL:
    - https://github.com/owner/repo

Examples:
    python3 add_pr_links.py --repo https://github.com/0xMiden/miden-base --file CHANGELOG.md
"""

import argparse
import re
import sys

def normalize_repo_url(repo_input):
    """
    Normalize repository input to a pull request URL.
    
    Args:
        repo_input: Full GitHub URL "https://github.com/owner/repo"
    
    Returns:
        The base URL for pull requests: "https://github.com/owner/repo/pull"
    """
    if not repo_input.startswith("https://github.com/"):
        raise ValueError(f"Invalid repository format: {repo_input}. Must be full GitHub URL (https://github.com/owner/repo).")
    
    base_url = repo_input.rstrip("/")
    return f"{base_url}/pull"

def process_changelog(filename, repo_url):
    """Process the changelog file to add PR links."""
    
    # Read the file
    try:
        with open(filename, 'r', encoding='utf-8') as file:
            content = file.read()
    except FileNotFoundError:
        print(f"Error: File '{filename}' not found.")
        return False
    except Exception as e:
        print(f"Error reading file: {e}")
        return False
    
    # Pattern to match PR numbers that are NOT already linked
    # This matches (#1234) or (#1234, #5678, #9012) but NOT ([#1234](link))
    pattern = r'(?<!\[)#(\d+)(?!\]\([^)]+\))'
    
    def replace_pr_number(match):
        """Replace a single PR number with a linked version."""
        pr_number = match.group(1)
        return f'[#{pr_number}]({repo_url}/{pr_number})'
    
    # Replace all unlinked PR numbers
    original_content = content
    content = re.sub(pattern, replace_pr_number, content)
    
    # Count changes made
    changes_made = len(re.findall(pattern, original_content))
    
    if changes_made == 0:
        print("No unlinked PR numbers found.")
        return True
    
    # Write the updated content back to file
    try:
        with open(filename, 'w', encoding='utf-8') as file:
            file.write(content)
        print(f"Successfully updated {changes_made} PR number(s) in {filename}")
        print(f"Using repository: {repo_url}")
        return True
    except Exception as e:
        print(f"Error writing file: {e}")
        return False

def main():
    """Main function."""
    parser = argparse.ArgumentParser(
        description="Convert bare PR numbers in changelog to linkable GitHub PR links.",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  python3 %(prog)s --repo https://github.com/0xMiden/miden-base --file CHANGELOG.md

Repository format:
  - Full GitHub URL (e.g., "https://github.com/owner/repo")
        """
    )
    
    parser.add_argument(
        '--repo', '-r',
        required=True,
        help='GitHub repository URL (https://github.com/owner/repo)'
    )
    parser.add_argument(
        '--file', '-f',
        required=True,
        help='Changelog filename'
    )
    
    args = parser.parse_args()
    
    try:
        repo_url = normalize_repo_url(args.repo)
    except ValueError as e:
        print(f"Error: {e}")
        sys.exit(1)
    
    success = process_changelog(args.file, repo_url)
    sys.exit(0 if success else 1)

if __name__ == "__main__":
    main()