Move to numpy version 2

[davidhassell]

cfdm currently fails for numpy 2.0.0 (release notes), released 16 Jun 2024.

We need to fix this.

I'm in favour of only supporting numpy v2. A whole bunch of our other new dependencies are for versions June 2024 or later, so I don't see the problem in only supporting numpy from that time, too.

[davidhassell]

Having had look, the call signature of some methods will have to change (e.g. __array__), so supporting both would be tricky ...

[davidhassell]

Looking through the numpy 2 migration guide: https://numpy.org/devdocs/numpy_2_0_migration_guide.html, I think it should quite straight forward.

PR to follow (but not until the CFA PR has been merged)

[sadielbartholomew]

Thanks David. Note some folk noticed Numpy-2 related issues downstream in cf-python so I created a label on that Issue Tracker: https://github.com/NCAS-CMS/cf-python/labels/numpy-2. Only one open at the moment, I see, but we should check it gets resolved before we convince ourselves we're comaptible with Numpy 2.

[davidhassell]

Thanks for the cross-reference. The changes for cfdm turned out to be minimal - I'm assuming that the same will be True for cf-python (... but am wondering whether all of cf-python's dependencies are v2 yet, ESMF?)

[sadielbartholomew]

I'm assuming that the same will be True for cf-python

Hopefully! But would be good to check 🙂