fix #24315: Wrong status referrers-not-all-downloaded for restriction relation, Warning message when trying to delete

This adds code to set the flag for those relations in the downloaded area which have no child relations.

git-svn-id: https://josm.openstreetmap.de/svn/trunk@19406 0c6e7542-c601-0410-84e7-c038aed88b3b

Author: GerdP

src/org/openstreetmap/josm/io/BoundingBoxDownloader.java

@@ -233,6 +233,8 @@ public DataSet parseOsm(ProgressMonitor progressMonitor) throws OsmTransferExcep
                 ds.getNodes().stream().filter(n -> bounds.stream().anyMatch(b -> b.contains(n)))
                         .forEach(i -> i.setReferrersDownloaded(true));
                 ds.getWays().forEach(i -> i.setReferrersDownloaded(true));
+                ds.getRelations().stream().filter(r -> r.getMembers().stream().noneMatch(rm -> rm.isRelation()))
+                        .forEach(i -> i.setReferrersDownloaded(true));
             }
             return ds;
         } catch (OsmTransferException e) {