Applicability of __debug__ for console_scripts

[itcarroll (Ian Carroll)]

I’m interested in any route(s) to making the -O argument, and thus the __debug__ builtin, useful in console scripts. On some systems, you can manually change the shebang in the executable written during installation to #!python -O to turn off __debug__. How could that be automated?

I see that a prior discussion (23842) on interpreter options led @jack1142 to mention the -O argument (and not for the first time, apparently ;). The action suggested was to see if any of the “wheel installers” would consider. Sorry for my ignorance, but who is that? Is pip a wheel installer? Is hatchling/setuptools/flit/pdm a wheel installer?

Is there any alternative to modifying the shebang? My understanding is that the -O flag influences the import mechanism to create or use __pycache__ files with the .opt-1.pyc extension. Sorry (again) if this is way off base, but can the import mechanism be configured after startup to create or use .opt-1.pyc files? My idea here is whether the executable itself can configure the import of the callable specified as the entry point.

[brettcannon]

@itcarroll

The action suggested was to see if any of the “wheel installers” would consider. Sorry for my ignorance, but who is that? Is pip a wheel installer? Is hatchling/setuptools/flit/pdm a wheel installer?

Yes, they all are. Any tool that installs Python packages would be a “wheel installer”.

@itcarroll

My understanding is that the -O flag influences the import mechanism to create or use __pycache__ files with the .opt-1.pyc extension.

Correct, ignoring the dropping of assert statements and __debug__ to False.

@itcarroll

but can the import mechanism be configured after startup to create or use .opt-1.pyc files?

With some effort, yes. You would have to swap out all the import-related parts with finders that returned loaders that only loaded opt-1.pyc files. You may want to also set it up so you write out the .opt-1.pyc files.

The sys module has the places to update and importlib has the code to help you. But I will say it’s a lot of state to update and it can be easy to miss something.

[pitrou (Antoine Pitrou)]

@itcarroll

I’m interested in any route(s) to making the -O argument, and thus the __debug__ builtin, useful in console scripts.

Note that the -O option doesn’t achieve much. You should measure if it gives you any practical benefit (chances are it doesn’t) before trying to enable it in your build chain.