Numpy failing in test code (`round_and_hash_float_array`)

[VeckoTheGecko]

Parcels version

main

Description

Getting CI failures from our test suite in #2522 and #2529

Parcels/tests/utils.py

Lines 141 to 153 in b7d6de8

	def round_and_hash_float_array(arr, decimals=6):
	arr = np.round(arr, decimals=decimals)
	# Adapted from https://cs.stackexchange.com/a/37965
	h = 1
	for f in arr:
	# Mimic Float.floatToIntBits: converts float to 4-byte binary, then interprets as int
	float_as_int = struct.unpack("!i", struct.pack("!f", f))[0]
	h = 31 * h + float_as_int
	# Mimic Java's HashMap hash transformation
	h ^= (h >> 20) ^ (h >> 12)
	return h ^ (h >> 7) ^ (h >> 4)

We should have been paying more attention to our warnings, since now in numpy 2.4.2 we have failures :)

Code sample

# test.py
import numpy as np
import struct

struct.pack("!f", np.array([261], dtype="int32"))

uv run test.py --with "numpy==2.3.5"
/Users/Hodgs004/coding/repos/parcels/numpy-bug/test.py:4: DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)
  struct.pack("!f", np.array([261], dtype="int32"))