clean up equality fix

Author: stephenworsley

docs/iris/src/whatsnew/contributions_3.0.0/bugfix_2019-Nov-19_cell_measure_copy_loss.txt

@@ -0,0 +1,2 @@
+* Copying a cube would previously ignore any attached class:`iris.coords.CellMeasure`.
+  These are now copied over.

lib/iris/analysis/__init__.py

@@ -186,7 +186,7 @@ def matches_any(self, predicate):
         return any(self.matches(predicate))
 
 
-def coord_comparison(*cubes, object_type="coord"):
+def coord_comparison(*cubes, object_get=None):
     """
     Convenience function to help compare coordinates on one or more cubes
     by their metadata.
@@ -240,14 +240,12 @@ def coord_comparison(*cubes, object_type="coord"):
         print('All equal coordinates: ', result['equal'])
 
     """
-    if object_type == "coord":
-        all_coords = [cube.coords() for cube in cubes]
-    elif object_type == "cell measure":
-        all_coords = [cube.cell_measures() for cube in cubes]
-    elif object_type == "ancillary variable":
-        all_coords = [cube.ancillary_variables() for cube in cubes]
-    else:
-        raise Exception
+    if object_get is None:
+        from iris.cube import Cube
+
+        object_get = Cube.coords
+
+    all_coords = [object_get(cube) for cube in cubes]
     grouped_coords = []
 
     # set of coordinates id()s of coordinates which have been processed
@@ -341,31 +339,15 @@ def diff_shape_fn(cube, coord):
         # dimension on their respective cubes
         # (None -> group describes a different dimension)
         def diff_data_dim_fn(cube, coord):
-            if object_type == "coord":
-                return cube.coord_dims(coord) != first_cube.coord_dims(
-                    first_coord
-                )
-            elif object_type == "cell measure":
-                return cube.cell_measure_dims(
-                    coord
-                ) != first_cube.cell_measure_dims(first_coord)
-            elif object_type == "ancillary variable":
-                return cube.ancillary_variable_dims(
-                    coord
-                ) != first_cube.ancillary_variable_dims(first_coord)
+            return coord.cube_dims(cube) != first_coord.cube_dims(first_cube)
 
         if coord_group.matches_any(diff_data_dim_fn):
             different_data_dimension.add(coord_group)
 
         # get all coordinate groups which don't describe a dimension
         # (None -> doesn't describe a dimension)
         def no_data_dim_fn(cube, coord):
-            if object_type == "coord":
-                return cube.coord_dims(coord) == ()
-            elif object_type == "cell measure":
-                return cube.cell_measure_dims(coord) == ()
-            elif object_type == "ancillary variable":
-                return cube.ancillary_variable_dims(coord) == ()
+            return coord.cube_dims(cube) == ()
 
         if coord_group.matches_all(no_data_dim_fn):
             no_data_dimension.add(coord_group)

lib/iris/cube.py

@@ -3576,7 +3576,7 @@ def __eq__(self, other):
 
             if result:
                 coord_comparison = iris.analysis.coord_comparison(
-                    self, other, object_type="cell measure",
+                    self, other, object_get=Cube.cell_measures,
                 )
                 # if there are any cell measures which are not equal
                 result = not (
@@ -3586,7 +3586,7 @@ def __eq__(self, other):
 
             if result:
                 coord_comparison = iris.analysis.coord_comparison(
-                    self, other, object_type="ancillary variable",
+                    self, other, object_get=Cube.ancillary_variables,
                 )
                 # if there are any ancillary variables which are not equal
                 result = not (