What Is an Editable Install?
An editable install (also called a “development install”) installs a Python package so that changes to the source code are immediately reflected in the environment without requiring reinstallation. This creates a live link between the package’s source code and the Python environment where it’s installed.
How Editable Installs Work
When you perform an editable install of a package, instead of copying the package files into your Python environment’s site-packages directory (as in a normal install), the package is installed using a special .pth file that points Python’s import system to your development directory containing the source code.
This means:
- Changes to your source code are immediately reflected when importing the package
- You don’t need to reinstall the package after each code change
- Your IDE can find and interact with the actual source code
- Any compiled extensions aren’t automatically rebuilt on changes
Limitations and Considerations
Editable installs have some limitations to keep in mind:
- Not all build backends support editable installs
- Compiled extensions require manual recompilation
- Editable installs can be fragile if source files are moved
- Some package features (like data files) may behave differently
Modern Editable Installs
PEP 660 introduced a standardized approach to editable installs that modern build backends can implement. This new mechanism addresses some historical limitations and inconsistencies across tools.
The implementation details vary by build backend, but the core concept remains: providing a development-friendly way to work on packages while testing them in a real Python environment.