feat(di-ordering): support multi-root diagrams

lib/features/di-ordering/BpmnDiOrdering.js

@@ -2,6 +2,7 @@ import { getDi } from '../../util/ModelUtil';
 
 import {
   filter,
+  forEach,
   map
 } from 'min-dash';
 
@@ -15,21 +16,24 @@ export default function BpmnDiOrdering(eventBus, canvas) {
   eventBus.on('saveXML.start', HIGH_PRIORITY, orderDi);
 
   function orderDi() {
-    var root = canvas.getRootElement(),
-        rootDi = getDi(root),
-        elements,
-        diElements;
+    var rootElements = canvas.getRootElements();
 
-    elements = selfAndAllChildren([ root ], false);
+    forEach(rootElements, function(root) {
+      var rootDi = getDi(root),
+          elements,
+          diElements;
 
-    // only bpmndi:Shape and bpmndi:Edge can be direct children of bpmndi:Plane
-    elements = filter(elements, function(element) {
-      return element !== root && !element.labelTarget;
+      elements = selfAndAllChildren([ root ], false);
+
+      // only bpmndi:Shape and bpmndi:Edge can be direct children of bpmndi:Plane
+      elements = filter(elements, function(element) {
+        return element !== root && !element.labelTarget;
+      });
+
+      diElements = map(elements, getDi);
+
+      rootDi.set('planeElement', diElements);
     });
-
-    diElements = map(elements, getDi);
-
-    rootDi.set('planeElement', diElements);
   }
 }
 

test/spec/features/ordering/BpmnDiOrderingSpec.js

@@ -109,6 +109,33 @@ describe('features/modeling - di ordering', function() {
         task1.id,
       ]);
     });
+
+    it('should order subprocess planes', function() {
+
+      // given
+      var canvas = getBpmnJS().get('canvas'),
+          root;
+
+      // when
+      var subProcess = add(
+        { type: 'bpmn:SubProcess', isExpanded: false, width: 300, height: 200 }, { x: 300, y: 200 }
+      );
+
+      var participant = add({ type: 'bpmn:Participant', width: 500, height: 300 }, { x: 300, y: 200 }),
+          task1 = add({ type: 'bpmn:Task' }, { x: 250, y: 200 }, subProcess.id + '_plane');
+
+      root = canvas.getRootElement();
+
+      // then
+      // subProcess id exists twice: once as collapsed shape and once as plane element
+      return expectDiOrder([
+        root.id,
+        participant.id,
+        subProcess.id,
+        subProcess.id,
+        task1.id,
+      ]);
+    });
   });