Can't collapse mesh #5377
Description
🐛 Bug Report
It's not possible to collapse a mesh cube.
There's an error as it tries to collapse the mesh coord.
return newcube.collapsed(coords, aggregator, **aggkeys)
File "/home/h02/bblay/.conda/envs/autoassess_new/lib/python3.10/site-packages/iris/cube.py", line 3904, in collapsed
collapsed_cube.replace_coord(coord.collapsed(local_dims))
File "/home/h02/bblay/.conda/envs/autoassess_new/lib/python3.10/site-packages/iris/coords.py", line 2284, in collapsed
coord = self.copy(points=points, bounds=bounds)
File "/home/h02/bblay/.conda/envs/autoassess_new/lib/python3.10/site-packages/iris/experimental/ugrid/mesh.py", line 2973, in copy
raise ValueError(msg)
ValueError: Cannot change the content of a MeshCoord.
@pp-mo suggests, "I think this is probably a little bug introduced because MeshCoords are "like" AuxCoords but a bit different.", and also suggests a workaround is to remove the mesh coords, "You need to index the cube on the mesh dimension, with something other than ':' or 'slice(None)'." e.g with cube[..., 0:] or cube[tuple(slice(0, None) for _ in cube.shape)]).
Environment
- Iris Version: 3.6