if name == 'main' vs Click: Package Entry Points

#python #cli #click #argparse

The Script That Stopped Working

You write a working Python script with if __name__ == "__main__" at the bottom. It runs fine from the command line. Then you turn it into a package, install it with pip, and suddenly your entry point doesn't work the way you expected. Import errors appear. Relative imports break. Configuration paths fail.

This happened to me when migrating a collection of data processing scripts into a proper package structure. The if __name__ == "__main__" pattern that worked perfectly for standalone scripts became a maintenance headache once I needed proper CLI arguments, subcommands, and distribution via PyPI.

The real question isn't which pattern to use — it's understanding what changes when you move from script-in-a-directory to installed-package-with-entry-points. The differences are subtle but critical.