Order to-be-created relations by dependencies in the changeset

modules/services/osm.js

@@ -314,6 +314,53 @@ export default {
             });
             return ordered;
         }
+        // sort relations in a changeset by dependencies
+        function sort(changes) {
+          // find a referenced relation in the current changeset
+          function resolve(item){
+            return _.find(relations, function(relation) {
+              return item.keyAttributes.type === 'relation'
+                && item.keyAttributes.ref === relation['@id'];
+            });
+          }
+          // a new item is an item that has not been already processed
+          function isNew(item) {
+            return !sorted[ item['@id'] ] && !_.find(processing, function(proc){
+             return proc['@id'] === item['@id'];
+            });
+          }
+          var processing = [],
+              sorted = {},
+              relations = changes.relation;
+
+          if (!relations) return changes;
+
+          for (var i = 0; i < relations.length; i++) {
+
+            var relation = relations[i];
+
+            // skip relation if already sorted
+            if ( !sorted[relation['@id']] ) {
+              processing.push( relation );
+            }
+
+            while ( processing.length > 0 ){
+              var next = processing[0],
+                  deps = _.filter( _.compact(next.member.map(resolve)), isNew);
+
+              if ( deps.length === 0 ){
+                sorted[ next['@id'] ] = next;
+                processing.shift();
+              } else {
+                processing = deps.concat( processing );
+              }
+            }
+
+          }
+
+          changes.relation = _.values(sorted);
+          return changes;
+        }
 
         function rep(entity) {
             return entity.asJXON(changeset_id);
@@ -323,7 +370,7 @@ export default {
             osmChange: {
                 '@version': 0.6,
                 '@generator': 'iD',
-                'create': nest(changes.created.map(rep), ['node', 'way', 'relation']),
+                'create': sort(nest(changes.created.map(rep), ['node', 'way', 'relation'])),
                 'modify': nest(changes.modified.map(rep), ['node', 'way', 'relation']),
                 'delete': _.extend(nest(changes.deleted.map(rep), ['relation', 'way', 'node']), {'@if-unused': true})
             }

test/spec/services/osm.js

@@ -362,6 +362,35 @@ describe('iD.serviceOsm', function () {
             ]);
         });
 
+        it('includes creations ordered by dependencies', function() {
+          var n = iD.Node({loc: [0, 0]}),
+              w = iD.Way({nodes: [n.id]}),
+              r1 = iD.Relation({members: [{id: w.id, type: 'way'}]}),
+              r2 = iD.Relation({members: [{id: r1.id, type: 'relation'}]}),
+              changes = {created: [r2, r1, w, n], modified: [], deleted: []},
+              jxon = connection.osmChangeJXON('1234', changes);
+
+          expect(d3.entries(jxon.osmChange.create)).to.eql([
+              {key: 'node', value: [n.asJXON('1234').node]},
+              {key: 'way', value: [w.asJXON('1234').way]},
+              {key: 'relation', value: [r1.asJXON('1234').relation, r2.asJXON('1234').relation]},
+          ]);
+        });
+
+        it('includes creations ignoring circular dependencies', function() {
+          var r1 = iD.Relation(),
+              r2 = iD.Relation(),
+              changes, jxon;
+          r1.addMember({id: r2.id, type: 'relation'});
+          r2.addMember({id: r1.id, type: 'relation'});
+          changes = {created: [r1,r2], modified: [], deleted: []};
+          jxon = connection.osmChangeJXON('1234', changes);
+
+          expect(d3.entries(jxon.osmChange.create)).to.eql([
+              {key: 'relation', value: [r1.asJXON('1234').relation, r2.asJXON('1234').relation]},
+          ]);
+        });
+
         it('includes modifications', function() {
             var n = iD.Node({loc: [0, 0]}),
                 w = iD.Way(),