Take axis values from master CDF as fallback if not provided by the main CDF

This fixes Speasy issue #223

Signed-off-by: Alexis Jeandet <[email protected]>

Author: jeandet

pyistp/_impl.py

@@ -34,18 +34,19 @@ def _get_attributes(master_cdf: Driver, cdf: Driver, var: str):
 
 
 def _get_axis(master_cdf: Driver, cdf: Driver, axis_var: str, data_var: str):
-    if cdf.has_variable(axis_var):
-        if cdf.is_char(axis_var):
+    src_cdf = cdf if cdf.has_variable(axis_var) else master_cdf if master_cdf.has_variable(axis_var) else None
+    if src_cdf is not None:
+        if src_cdf.is_char(axis_var):
             if 'sig_digits' in master_cdf.variable_attributes(axis_var):  # cluster CSA trick :/
-                return SupportDataVariable(name=axis_var, values=np.asarray(cdf.values(axis_var), dtype=float),
-                                           attributes=_get_attributes(master_cdf, cdf, axis_var),
-                                           is_nrv=cdf.is_nrv(axis_var),
-                                           cdf_type=cdf.cdf_type(axis_var)
+                return SupportDataVariable(name=axis_var, values=np.asarray(src_cdf.values(axis_var), dtype=float),
+                                           attributes=_get_attributes(master_cdf, src_cdf, axis_var),
+                                           is_nrv=src_cdf.is_nrv(axis_var),
+                                           cdf_type=src_cdf.cdf_type(axis_var)
                                            )
-        return SupportDataVariable(name=axis_var, values=cdf.values(axis_var),
-                                   attributes=_get_attributes(master_cdf, cdf, axis_var),
-                                   is_nrv=cdf.is_nrv(axis_var),
-                                   cdf_type=cdf.cdf_type(axis_var)
+        return SupportDataVariable(name=axis_var, values=src_cdf.values(axis_var),
+                                   attributes=_get_attributes(master_cdf, src_cdf, axis_var),
+                                   is_nrv=src_cdf.is_nrv(axis_var),
+                                   cdf_type=src_cdf.cdf_type(axis_var)
                                    )
     else:
         log.warning(

tests/resources/sta_l1_het_00000000_v01.cdf

@@ -117,8 +117,15 @@ def test_get_data_variable_type(self):
 
     def test_get_support_variable_type(self):
         istp_file = pyistp.load(file=f"{current_path}/resources/solo_l3_rpw-bia-density-10-seconds_00000000_v01.cdf")
-        self.assertEqual(istp_file.data_variable('DENSITY').axes[0].cdf_type, 'CDF_TIME_TT2000')  
+        self.assertEqual(istp_file.data_variable('DENSITY').axes[0].cdf_type, 'CDF_TIME_TT2000')
 
     def test_is_nrv(self):
         istp_file = pyistp.load(file=f"{current_path}/resources/solo_l3_rpw-bia-density-10-seconds_00000000_v01.cdf")
         self.assertFalse(istp_file.data_variable('DENSITY').axes[0].is_nrv)
+
+    def test_get_axis_values_from_master_as_fallback(self):
+        # https://github.com/SciQLop/speasy/issues/223
+        istp_file = pyistp.load(file=f"{current_path}/resources/sta_l1_het_20240103_v01.cdf",
+                                master_file=f"{current_path}/resources/sta_l1_het_00000000_v01.cdf")
+        self.assertIsNotNone(istp_file)
+        self.assertIsNotNone(istp_file.data_variable('Proton_Flux'))