Ensure "c::transport+base" items are str

Avoid TypeError in broadcast_wildcard() with mixed str and
sdmx.model.common.Code.

Author: khaeru

message_ix_models/model/transport/build.py

@@ -398,7 +398,12 @@ def add_structure(c: Computer) -> None:
     # - Multiple static and dynamic tasks generated in loops etc.
     tasks: list[tuple] = list(STRUCTURE_STATIC) + [
         ("c::transport", quote(spec.add.set["commodity"])),
-        ("c::transport+base", quote(spec.add.set["commodity"] + info.set["commodity"])),
+        # Convert to str to avoid TypeError in broadcast_wildcard → sorted()
+        # TODO Remove once sdmx.model.common.Code is sortable with str
+        (
+            "c::transport+base",
+            quote(list(map(str, spec.add.set["commodity"] + info.set["commodity"]))),
+        ),
         ("cg", quote(spec.add.set["consumer_group"])),
         ("indexers:cg", spec.add.set["consumer_group indexers"]),
         ("nodes", quote(info.set["node"])),

message_ix_models/report/operator.py

@@ -59,7 +59,7 @@ def broadcast_wildcard(
     """Broadcast over coordinates `coords` along respective dimension(s) `dim`.
 
     `dim` may identify a single dimension or a sequence of dimensions; `coords` must
-    be given for each dimension
+    be given for each dimension.
 
     For each respective items from `dim` and `coords`, any missing coordinates along the
     dimension are populated using the values of `qty` keyed with the 'wildcard' label