`pkg_resources` deprecation

[rossjjennings]

While debugging some issues with a new environment, I noticed that from enterprise.pulsar import Pulsar raises a DeprecationWarning:

[...]/enterprise/signals/utils.py:13: UserWarning: pkg_resources is deprecated as an API.
See https://setuptools.pypa.io/en/latest/pkg_resources.html.
The pkg_resources package is slated for removal as early as 2025-11-30.
Refrain from using this package or pin to Setuptools<81.
  from pkg_resources import Requirement, resource_filename

Apparently pkg_resources (from setuptools), which is used in signals/utils.py, has been deprecated in favor of the native Python module importlib.resources.

[vhaasteren]

That function is weird. It is a literal copy-paste of a function of libstempo, and it uses the libstempo data file which is why it needs pkg_resources. Whoever uses that function should just import it from libstempo. No piece of code in enterprise uses it as far as I can see. I think we should simply delete the function make_ecc_interpolant from enterprise and be done with it. I do not see it being used in enterprise_extensions either.

What do you think, @AaronDJohnson ?

[AaronDJohnson]

Given that we don't require libstempo as a dependency anymore, I think it's important that we remove it. The function itself is only a call to scipy.interpolate.interp1d which can be performed in a single line, if it is needed.

[vhaasteren]

Exactly

And even then, doing an import libstempo.toasim.make_ecc_interpolant would provide the functionality