Handle incomplete relations

js/id/graph/relation.js

@@ -4,11 +4,13 @@ iD.Relation = iD.Entity.extend({
 
     extent: function(resolver) {
         return resolver.transient(this, 'extent', function() {
-            var extent = iD.geo.Extent();
-            for (var i = 0, l = this.members.length; i < l; i++) {
-                extent = extent.extend(resolver.entity(this.members[i].id).extent(resolver));
-            }
-            return extent;
+            return this.members.reduce(function (extent, member) {
+                if (member = resolver.entity(member.id)) {
+                    return extent.extend(member.extent(resolver))
+                } else {
+                    return extent;
+                }
+            }, iD.geo.Extent());
         });
     },
 
@@ -28,7 +30,7 @@ iD.Relation = iD.Entity.extend({
     //
     multipolygon: function(resolver) {
         var members = this.members
-            .filter(function (m) { return m.type === 'way'; })
+            .filter(function (m) { return m.type === 'way' && resolver.entity(m.id); })
             .map(function (m) { return { role: m.role || 'outer', id: m.id, nodes: resolver.fetch(m.id).nodes }; });
 
         function join(ways) {

test/spec/graph/relation.js

@@ -44,6 +44,15 @@ describe('iD.Relation', function () {
 
             expect(r.extent(graph)).to.eql([[0, 0], [5, 10]])
         });
+
+        it("returns the known extent of incomplete relations", function () {
+            var a = iD.Node({loc: [0, 0]}),
+                b = iD.Node({loc: [5, 10]}),
+                r = iD.Relation({members: [{id: a.id}, {id: b.id}]}),
+                graph = iD.Graph([a, r]);
+
+            expect(r.extent(graph)).to.eql([[0, 0], [0, 0]])
+        });
     });
 
     describe("#multipolygon", function () {
@@ -239,5 +248,17 @@ describe('iD.Relation', function () {
 
             expect(r.multipolygon(graph)).to.eql([[[a, b, c, a], [d, e, f, d]], [[g, h, i, g]]]);
         });
+
+        specify("incomplete relation", function () {
+            var a  = iD.Node(),
+                b  = iD.Node(),
+                c  = iD.Node(),
+                w1 = iD.Way({nodes: [a.id, b.id, c.id]}),
+                w2 = iD.Way(),
+                r  = iD.Relation({members: [{id: w2.id, type: 'way'}, {id: w1.id, type: 'way'}]}),
+                g  = iD.Graph([a, b, c, w1, r]);
+
+            expect(r.multipolygon(g)).to.eql([[[a, b, c]]]);
+        });
     });
 });