Moving from Cookiecutter to Copier to solve the template update problem identified in the Cookiecutter GitHub Copilot project template post.

The Problem with Cookiecutter

Cookiecutter excels at creating new projects but cannot update existing projects when the template changes. This is particularly problematic for frequently evolving files like copilot-instructions.md which I’m constantly refining as I learn better Copilot practices.

Why Copier

Copier addresses this limitation with its updating capability - it can apply template changes to existing projects, maintaining the original answers whilst incorporating new template features.

Migration Plan

• Migrate Existing CookieCutter Git Repo - Convert the cookiecutter-basic template structure to Copier format
• Translate Into A Copier Repo - Transform cookiecutter.json and template variables to Copier’s copier.yml format
• Apply To An Existing Project - Test the converted template on an existing project created with the old Cookiecutter template
• Update The Template Then Reapply To A Project - Verify the update workflow by modifying the template and applying changes to the existing project

Results

Migration completed successfully. Key steps carried out:

1. Repository Renamed - Renamed from cookiecutter-basic to copier-copilot-coding
2. Automated Migration - Used GitHub Copilot to handle the complete migration in one step:
   • Ported cookiecutter.json to copier.yml
   • Mapped {{cookiecutter.project_slug}} to {{project_name}}
   • Updated README.md and copilot-instructions.md to Copier style
   • Updated top-level README with Copier usage instructions

Critical Note: Remember to commit the created .copier-answers.yml file to git. Without this file committed, you cannot reapply template updates when the template changes. This answers file stores your original configuration choices and is essential for Copier’s update functionality.

The template is now ready for use with Copier’s updating capabilities.