Removed unneccessary theoretical upperbound checks, removed early return of true, added more precise method of getting the upper bound, fixed lower and upper boundary checks.

Author: david-sh-csiro

src/emsarray/conventions/ugrid.py

@@ -748,30 +748,19 @@ def has_valid_face_edge_connectivity(self) -> bool:
             )
             return False
 
-        try:
+        if '_FillValue' in data_array.encoding:
             fill_value = data_array.encoding['_FillValue']
-        except KeyError:
-            return True
-
-        lower_bound = _get_start_index(data_array)
-        theoretical_upper_bound = self.face_count * self.max_node_count
-        actual_upper_bound = numpy.nanmax(data_array)
 
-        if lower_bound < fill_value < actual_upper_bound:
-            warnings.warn(
-                f"Got a face_edge_connectivity variable {data_array.name!r} with "
-                f"a _FillValue inside the actual index range",
-                ConventionViolationWarning,
-            )
-            return False
+            lower_bound = _get_start_index(data_array)
+            upper_bound = self.edge_count + lower_bound
 
-        if lower_bound < fill_value < theoretical_upper_bound:
-            warnings.warn(
-                f"Got a face_edge_connectivity variable {data_array.name!r} with "
-                f"a _FillValue inside the theoretical index range",
-                ConventionViolationWarning,
-            )
-            return False
+            if lower_bound <= fill_value <= upper_bound:
+                warnings.warn(
+                    f"Got a face_edge_connectivity variable {data_array.name!r} with "
+                    f"a _FillValue inside the actual index range",
+                    ConventionViolationWarning,
+                )
+                return False
 
         return True