`nisar.h5.h5utils.extractScalar` broken with h5py 3.15.1 and HDF5 2.0.0

[piyushrpt]

I was able to successfully build isce3 with HDF5 2.0.0 but it looks like the extractScalar method fails with

TypeError: only 0-dimensional arrays can be converted to Python scalars

In an ipython console, I can confirm that h5py now returns an array of 1 element instead of a scalar.

I also had to explicitly build isce3 using -DCMAKE_POLICY_VERSION_MINIMUM=3.5 as gtest requirements break building isce3 with newer versions of cmake.

[piyushrpt]

The patch needed to fix the issue would be as follows. Not sure if PRs are being accepted

*** packages/nisar/h5/h5utils.py	2026-02-18 14:02:22
--- packages/nisar/h5/h5utils.py	2024-11-01 20:39:59
*************** def extractScalar(h5grp, key, destType, logger=None, m
*** 23,29 ****

      try:
          val = h5grp[key][()]
!         val = destType(val.item() if hasattr(val, "item") else val)
      except KeyError as e:
          raise KeyError(handle_message(f'{key} not found at {h5grp.name}')) from e
      except Exception as e:
--- 23,29 ----

      try:
          val = h5grp[key][()]
!         val = destType(val)
      except KeyError as e:
          raise KeyError(handle_message(f'{key} not found at {h5grp.name}')) from e
      except Exception as e:

[piyushrpt]

Addressed in #226
There may be other locations in workflows where population of scalar data in HDF5 files could be impacted.