Add Pystp netcdf driver

[RichardHitier]

No description provided.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jeandet]

Code review

Found 1 issue:

1. cdf_type() is inconsistent with values() for CDF_EPOCH variables. values() calls _get_units() which checks both 'units' and 'UNITS', and routes through _is_cdf_epoch() to return datetime64[ns]. cdf_type() only calls v.getncattr('units') (lowercase) and only handles the CF time ('since' in units) branch — there is no CDF_EPOCH branch at all. Verified against the bundled tests/resources/ac_h2s_mfi_cdaweb.nc (whose Epoch has UNITS='ms'): values('Epoch').dtype is datetime64[ns] while cdf_type('Epoch') returns 'CDF_DOUBLE'. Downstream consumers that key off cdf_type to identify time axes will misclassify the epoch.

PyISTP/pyistp/drivers/netcdf.py

Lines 128 to 141 in ec4e33c

	def cdf_type(self, var):
	v = self._ds[var]
	# CF time variable: float with a "units" attribute containing "since"
	try:
	units = v.getncattr('units')
	if isinstance(units, str) and 'since' in units:
	return 'CDF_TIME_TT2000'
	except AttributeError:
	pass
	if v.dtype == str:
	return 'CDF_CHAR'
	dtype_str = v.dtype.str.lstrip('<>=!')
	return self._DTYPE_TO_CDF.get(dtype_str, f'CDF_UNKNOWN_{dtype_str}')

Suggest reusing _get_units() and adding a _is_cdf_epoch(var) branch returning 'CDF_EPOCH' (mirroring values()).

Other items considered but not flagged: netCDF4.Dataset is never closed (no close()/context manager) and the _DTYPE_TO_CDF 'S' key is unreachable (v.dtype.str.lstrip('<>=!') leaves the leading |) — both real but lower-impact; worth a follow-up.

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