DEP: extend deprecation of private namespaces also to fortran-generated modules #19907
Description
While looking at cleaning up the deprecations following #18279 (fitting into the larger picture of #14360), I noticed that scipy.interpolate.dfitpack is not deprecated, which seems like an oversight - in particular because it contains several functions that scipy.interpolate itself contains:
>>> import scipy.interpolate
>>> import scipy.interpolate.dfitpack
>>> dfitpack_funcs = set(scipy.interpolate.dfitpack.__dir__())
>>> interpolate_funcs = set(scipy.interpolate.__dir__())
>>> sorted([x for x in dfitpack_funcs & interpolate_funcs if not x.startswith("_")])
['spalde', 'splder', 'splev', 'splint', 'sproot']But that's only half the story, because we have a new interface to fitpack...
scipy/scipy/interpolate/__init__.py
Lines 170 to 171 in 5273257
and funnily enough that file wraps both
dfitpack directly, as well as a separate wrapper layer, also around dfitpack (sidenote: looks like this tweet I saw today turned out to be prophetic 😅 ). Suffice it to say, despite different names, a lot (all?) of the remaining functions in dfitpack then also get accounted for.
It's looks likely that this was overlooked because there's no actual python code, we just directly generate the functions from fortran:
scipy/scipy/interpolate/meson.build
Lines 145 to 162 in 5273257
Not sure how many other such should-be-private-but-has-no-underscore fortran libraries are about.