fix(modeling): properly cascade label deletion

Ensure we execute the following nicely:

* unset name -> remove label shape
* remove label shape -> unset name

lib/features/label-editing/cmd/UpdateLabelHandler.js

@@ -54,7 +54,7 @@ export default function UpdateLabelHandler(modeling, textRenderer) {
     if (!isLabel(element)
         && isLabelExternal(element)
         && !hasExternalLabel(element)
-        && newLabel !== '') {
+        && !isEmptyText(newLabel)) {
 
       // create label
       var paddingTop = 7;
@@ -86,10 +86,14 @@ export default function UpdateLabelHandler(modeling, textRenderer) {
     var element = ctx.element,
         label = element.label || element,
         newLabel = ctx.newLabel,
-        newBounds = ctx.newBounds;
+        newBounds = ctx.newBounds,
+        hints = ctx.hints || {};
 
-    if (isLabel(label) && newLabel.trim() === '') {
-      modeling.removeShape(label);
+    if (isLabel(label) && isEmptyText(newLabel)) {
+
+      if (hints.removeShape !== false) {
+        modeling.removeShape(label, { unsetLabel: false });
+      }
 
       return;
     }
@@ -132,3 +136,10 @@ UpdateLabelHandler.$inject = [
   'modeling',
   'textRenderer'
 ];
+
+
+// helpers ///////////////////////
+
+function isEmptyText(label) {
+  return !label || !label.trim();
+}

lib/features/modeling/Modeling.js

@@ -58,11 +58,12 @@ Modeling.prototype.getHandlers = function() {
 };
 
 
-Modeling.prototype.updateLabel = function(element, newLabel, newBounds) {
+Modeling.prototype.updateLabel = function(element, newLabel, newBounds, hints) {
   this._commandStack.execute('element.updateLabel', {
     element: element,
     newLabel: newLabel,
-    newBounds: newBounds
+    newBounds: newBounds,
+    hints: hints || {}
   });
 };
 

lib/features/modeling/behavior/LabelBehavior.js

@@ -89,11 +89,12 @@ export default function LabelBehavior(
   // update label after label shape was deleted
   this.postExecute('shape.delete', function(event) {
     var context = event.context,
-        shape = context;
+        labelTarget = context.labelTarget,
+        hints = context.hints || {};
 
     // check if label
-    if (shape.labelTarget) {
-      modeling.updateLabel(shape.labelTarget, '');
+    if (labelTarget && hints.unsetLabel !== false) {
+      modeling.updateLabel(labelTarget, '', null, { removeShape: false });
     }
   });
 

test/spec/features/modeling/UpdateLabelSpec.js

@@ -50,7 +50,25 @@ describe('features/modeling - update label', function() {
   ));
 
 
-  it('should delete label when setting empty string', inject(
+  describe('should delete label', function() {
+
+    it('when setting null', inject(
+      function(modeling, elementRegistry) {
+
+        // given
+        var startEvent_1 = elementRegistry.get('StartEvent_1');
+
+        // when
+        modeling.updateLabel(startEvent_1, null);
+
+        // then
+        expect(startEvent_1.businessObject.name).not.to.exist;
+        expect(startEvent_1.label).not.to.exist;
+      }
+    ));
+
+
+    it('when setting empty string', inject(
       function(modeling, elementRegistry) {
 
         // given
@@ -65,6 +83,8 @@ describe('features/modeling - update label', function() {
       }
     ));
 
+  });
+
 
   it('should change name of start event when editing label', inject(
     function(modeling, elementRegistry) {