Open editor with llm proposed branch name + branch name from first line. Creates branch based on origin/main and cherry-picks commit onto it. Generated by Claude 3.5 sonnet

git-auto-branch.py

#!/usr/bin/env python3

import subprocess
import sys
import tempfile
import os
import re

def run_git_command(command, error_message="Git command failed"):
    """
    Run a git command and handle errors consistently.

    Args:
        command (list): Command and arguments to run
        error_message (str): Message to include in error if command fails

    Returns:
        str: Command output

    Raises:
        subprocess.CalledProcessError: If command fails
    """
    result = subprocess.run(
        command,
        capture_output=True,
        text=True,
        check=True
    )
    return result.stdout.strip()

def get_editor():
    """Get the default editor from git config or environment"""
    try:
        return run_git_command(['git', 'config', 'core.editor'])
    except subprocess.CalledProcessError:
        return os.environ.get('EDITOR', 'vim')

def edit_branch_name(initial_content):
    """
    Open the default editor with initial content and return the edited content

    Args:
        initial_content (str): Content to pre-fill in the editor

    Returns:
        str: The edited content after save
    """
    editor = get_editor()

    with tempfile.NamedTemporaryFile(mode='w+', suffix='.txt') as tf:
        # Write initial content
        tf.write(initial_content)
        tf.flush()

        # Open editor
        subprocess.run([editor, tf.name], check=True)

        # Read back the edited content
        tf.seek(0)
        return tf.read().strip()

def commit_message_to_branch_name(commit_message):
    """
    Convert a commit message to a branch name by:
    - Replacing any non-alphanumeric character with a hyphen
    - Collapsing multiple hyphens into one
    - Removing leading/trailing hyphens

    Args:
        commit_message (str): The commit message to convert

    Returns:
        str: The formatted branch name

    Examples:
        >>> commit_message_to_branch_name("edits_since_last")
        'edits-since-last'
        >>> commit_message_to_branch_name("Fix: User Auth!!")
        'Fix-User-Auth'
    """
    # Replace any non-alphanumeric character with a hyphen
    name = re.sub(r'[^a-zA-Z0-9]+', '-', commit_message.lower())
    # Remove leading/trailing hyphens
    return name.strip('-')

def check_and_create_branch():
    """
    Check repository status and create a new branch based on the commit message.

    Returns:
        tuple: (bool, str) - (success status, error message if any)
    """
    try:
        # Check git status
        status_result = run_git_command(
            ['git', 'status', '--untracked-files=no', '--porcelain']
        )

        if status_result:
            return False, "Repository has uncommitted changes"

        # Get the current HEAD commit SHA
        current_sha = run_git_command(['git', 'rev-parse', 'HEAD'])

        # Get all commits in main branch
        main_commits = run_git_command(['git', 'rev-list', 'origin/main']).split('\n')

        if current_sha in main_commits:
            return False, "HEAD commit is already in main branch"

        # Get the current commit message
        commit_message = run_git_command(['git', 'log', '-1', '--pretty=%B'])

        branch_name = commit_message_to_branch_name(commit_message)

        # Generate branch name suggestion using llm
        prompt = f"Generate a git branch name (using only alphanumeric characters and hyphens) for this commit message:\n\n{commit_message}\n\nOutput only the branch name, nothing else."

        try:
            suggested_name = subprocess.run(
                ['llm', 'prompt', prompt],
                capture_output=True,
                text=True,
                check=True
            ).stdout.strip()
        except subprocess.CalledProcessError as e:
            return False, f"Failed to generate branch name using llm: {e.stderr}"

        # Open editor for confirmation/modification
        final_branch_name = edit_branch_name(suggested_name + "\n" + branch_name)

        if not final_branch_name:
            return False, "No branch name provided"

        # Create and checkout new branch
        run_git_command(['git', 'checkout', '-b', final_branch_name, 'origin/main'])

        # Cherry-pick the stored commit
        run_git_command(['git', 'cherry-pick', current_sha])

        return True, f"Successfully created and switched to branch '{final_branch_name}'"

    except subprocess.CalledProcessError as e:
        return False, f"Git command failed: {e.stderr}"
    except Exception as e:
        return False, f"Unexpected error: {str(e)}"

if __name__ == "__main__":
    success, message = check_and_create_branch()
    print(message)
    sys.exit(0 if success else 1)