pyfabm: use correct metadata for coupled diagnostics

src/pyfabm/__init__.py

@@ -602,9 +602,12 @@ def __init__(
             self.model.fabm.variable_get_metadata(
                 variable_pointer, ATTRIBUTE_LENGTH, strname, strunits, strlong_name
             )
-            name = strname.value.decode("ascii")
-            units = strunits.value.decode("ascii")
-            long_name = strlong_name.value.decode("ascii")
+            if name is None:
+                name = strname.value.decode("ascii")
+            if units is None:
+                units = strunits.value.decode("ascii")
+            if long_name is None:
+                long_name = strlong_name.value.decode("ascii")
             self.properties = VariableProperties(self.model, self.variable_pointer)
 
         self.name = name
@@ -730,11 +733,17 @@ class DiagnosticVariable(Variable):
     def __init__(
         self,
         model: "Model",
+        name: str,
+        units: str,
+        long_name: str,
+        path: str,
         variable_pointer: ctypes.c_void_p,
         index: int,
         horizontal: bool,
     ):
-        Variable.__init__(self, model, variable_pointer=variable_pointer)
+        Variable.__init__(
+            self, model, name, units, long_name, path, variable_pointer=variable_pointer
+        )
         self.data = None
         self.horizontal = horizontal
         self.index = index
@@ -749,13 +758,13 @@ def output(self) -> bool:
         return self.model.fabm.variable_get_output(self.variable_pointer) != 0
 
     def setSave(self, value: bool):
-        self.model.fabm.set_variable_save(
-            self.model.pmodel,
+        vartype = (
             HORIZONTAL_DIAGNOSTIC_VARIABLE
             if self.horizontal
-            else INTERIOR_DIAGNOSTIC_VARIABLE,
-            self.index,
-            1 if value else 0,
+            else INTERIOR_DIAGNOSTIC_VARIABLE
+        )
+        self.model.fabm.set_variable_save(
+            self.model.pmodel, vartype, self.index, 1 if value else 0
         )
 
     save = property(fset=setSave)
@@ -1283,18 +1292,56 @@ def updateConfiguration(self, settings=None):
                 StateVariable(self, ptr, self._bottom_state[i, ...])
             )
         for i in range(ndiag_interior.value):
+            self.fabm.get_variable_metadata(
+                self.pmodel,
+                INTERIOR_DIAGNOSTIC_VARIABLE,
+                i + 1,
+                ATTRIBUTE_LENGTH,
+                strname,
+                strunits,
+                strlong_name,
+                strpath,
+            )
             ptr = self.fabm.get_variable(
                 self.pmodel, INTERIOR_DIAGNOSTIC_VARIABLE, i + 1
             )
             self.interior_diagnostic_variables._data.append(
-                DiagnosticVariable(self, ptr, i + 1, False)
+                DiagnosticVariable(
+                    self,
+                    strname.value.decode("ascii"),
+                    strunits.value.decode("ascii"),
+                    strlong_name.value.decode("ascii"),
+                    strpath.value.decode("ascii"),
+                    ptr,
+                    i + 1,
+                    False,
+                )
             )
         for i in range(ndiag_horizontal.value):
+            self.fabm.get_variable_metadata(
+                self.pmodel,
+                HORIZONTAL_DIAGNOSTIC_VARIABLE,
+                i + 1,
+                ATTRIBUTE_LENGTH,
+                strname,
+                strunits,
+                strlong_name,
+                strpath,
+            )
             ptr = self.fabm.get_variable(
                 self.pmodel, HORIZONTAL_DIAGNOSTIC_VARIABLE, i + 1
             )
             self.horizontal_diagnostic_variables._data.append(
-                DiagnosticVariable(self, ptr, i + 1, True)
+                DiagnosticVariable(
+                    self,
+                    strname.value.decode("ascii"),
+                    strunits.value.decode("ascii"),
+                    strlong_name.value.decode("ascii"),
+                    strpath.value.decode("ascii"),
+                    ptr,
+                    i + 1,
+                    True,
+                )
             )
         for i in range(ndependencies_interior.value):
             ptr = self.fabm.get_variable(self.pmodel, INTERIOR_DEPENDENCY, i + 1)