Drop the claimed_by & disputed_by tags after we're done using them.

integration-test/1810-alternate-viewpoints.py

@@ -101,6 +101,10 @@ def test_boundary(self):
                 'kind': 'unrecognized_country',
                 'kind:xx': 'country',
                 'name': 'XX Claim',
+
+                # we should have dropped the claimed_by/disputed_by tags
+                'claimed_by': type(None),
+                'disputed_by': type(None),
             })
 
         # should get a section recognised _except_ by XX

queries.yaml

@@ -716,6 +716,21 @@ post_process:
       base_layer: boundaries
       start_zoom: 8
 
+  # drop the claimed_by, disputed_by (and any left/right versions) on any
+  # borders. these should have been projected into kind:xx viewpoints in the
+  # previous step.
+  - fn: vectordatasource.transform.drop_properties
+    params:
+      source_layer: boundaries
+      start_zoom: 8
+      properties:
+        - claimed_by
+        - "claimed_by:left"
+        - "claimed_by:right"
+        - disputed_by
+        - "disputed_by:left"
+        - "disputed_by:right"
+
   # drop id/id:left/id:right on boundaries up to zoom 12 inclusive.
   # the left/right IDs tend to be unique as a pair, and so prevent merging.
   # the id itself will be dropped by merging if it's possible to merge, and