API: Update arraypad,arraysetops, ufunclike and utils namespaces in np.lib

[mtsokol]

Relevant issue #24507

Hi @rgommers @ngoldbaum,

This PR moves lib.arraypad, lib.arraysetops, lib.ufunclike and lib.utils modules to private files and ensures that their public methods are only available through the main namespace. There are no additional functions available from their local namespaces.

I decided to join those four submodules together as they have small number of functions (e.g. arraypad has only one).

[ngoldbaum]

len(np.lib.__all__) drops from 87 to 71 with this PR. Everything removed is still available in the top-level namespace.

[ngoldbaum]

I'm seeing some downstream use of patterns like this:

unique_src_ids = np.lib.arraysetops.unique(src_ids) 

It would probably be worthwhile to add errors redirecting people to the main namespace or whichever other migration path is appropriate for that submodule if they try to access any np.lib submodules we're removing.

[ngoldbaum]

It would probably be worthwhile to add errors redirecting people to the main namespace or whichever other migration path is appropriate for that submodule if they try to access any np.lib submodules we're removing.

This could be a followup though, no need to hold up merging this, which looks good otherwise except for the one issue I pointed out in the docs.

[mtsokol]

It would probably be worthwhile to add errors redirecting people to the main namespace or whichever other migration path is appropriate for that submodule if they try to access any np.lib submodules we're removing.

This could be a followup though, no need to hold up merging this, which looks good otherwise except for the one issue I pointed out in the docs.

@ngoldbaum I think that's a good point - I added it here to def __getattr__(): in numpy/lib/__init__.py. If a user wants to access a function from a lib module like:

np.lib.arraysetops.unique(src_ids) 

The message says:

AttributeError: `np.lib.arraysetops` is now private. Function that you're looking for should be available from the main namespace `np.*`

[ngoldbaum]

Let's merge this one as well so the other np.lib PRs can get updated to add to the __getattr__ error. Thanks for dealing with all the merge conflicts and making the PR diffs a lot smaller!