added cubelist errors

lib/iris/_concatenate.py

@@ -572,7 +572,11 @@ def concatenate(
         A :class:`iris.cube.CubeList` of concatenated :class:`iris.cube.Cube` instances.
 
     """
-    cube_signatures = [_CubeSignature(cube) for cube in cubes]
+    cube_signatures = []
+    for cube in cubes:
+        if cube.is_dataless():
+            raise iris.exceptions.DatalessError("concatenate")
+        cube_signatures.append(_CubeSignature(cube))
 
     proto_cubes: list[_ProtoCube] = []
     # Initialise the nominated axis (dimension) of concatenation

lib/iris/_lazy_data.py

@@ -16,6 +16,7 @@
 import dask.array as da
 import dask.config
 import dask.utils
+import iris.exceptions
 import numpy as np
 import numpy.ma as ma
 
@@ -317,7 +318,10 @@ def _co_realise_lazy_arrays(arrays):
         # Note : in some cases dask (and numpy) will return a scalar
         # numpy.int/numpy.float object rather than an ndarray.
         # Recorded in https://github.com/dask/dask/issues/2111.
-        real_out = np.asanyarray(real_out)
+        if real_out is not None:
+            real_out = np.asanyarray(real_out)
+        else:
+            raise iris.exceptions.DatalessError("realising")
         if isinstance(real_out, ma.core.MaskedConstant):
             # Convert any masked constants into NumPy masked arrays.
             # NOTE: in this case, also apply the original lazy-array dtype, as

lib/iris/_merge.py

@@ -1109,6 +1109,8 @@ def __init__(self, cube):
         source-cube.
 
         """
+        if cube.is_dataless():
+            raise iris.exceptions.DatalessError("merge")
         # Default hint ordering for candidate dimension coordinates.
         self._hints = [
             "time",
@@ -1289,6 +1291,8 @@ def register(self, cube, error_on_mismatch=False):
             this :class:`ProtoCube`.
 
         """
+        if cube.is_dataless():
+            raise iris.exceptions.DatalessError("merge")
         cube_signature = self._cube_signature
         other = self._build_signature(cube)
         match = cube_signature.match(other, error_on_mismatch)

lib/iris/cube.py

@@ -174,8 +174,6 @@ def _assert_is_cube(obj):
         if not hasattr(obj, "add_aux_coord"):
             msg = r"Object {obj} cannot be put in a cubelist, as it is not a Cube."
             raise ValueError(msg)
-        elif obj.is_dataless():
-            raise iris.exceptions.DatalessError("CubeList")
 
     def _repr_html_(self):
         from iris.experimental.representation import CubeListRepresentation
@@ -412,7 +410,6 @@ def merge_cube(self):
         """
         if not self:
             raise ValueError("can't merge an empty CubeList")
-
         # Register each of our cubes with a single ProtoCube.
         proto_cube = iris._merge.ProtoCube(self[0])
         for c in self[1:]: