From e8b34195bb50f1d126e49595ac9018685f9ffd6c Mon Sep 17 00:00:00 2001
From: Philipp Fromme <philippfromme@outlook.com>
Date: Thu, 10 Oct 2019 14:15:59 +0200
Subject: [PATCH] feat(attach-support): allow detaching multiple shapes

---
 lib/features/attach-support/AttachSupport.js  | 21 +++++++---
 .../attach-support/AttachSupportSpec.js       | 41 +++++++++++++++++--
 2 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/lib/features/attach-support/AttachSupport.js b/lib/features/attach-support/AttachSupport.js
index 2b0975d87..b4a6cbdd8 100644
--- a/lib/features/attach-support/AttachSupport.js
+++ b/lib/features/attach-support/AttachSupport.js
@@ -122,18 +122,21 @@ export default function AttachSupport(injector, eventBus, canvas, rules, modelin
         newHost = context.newHost,
         attachers;
 
-    // we only support attachment / detachment of one element
-    if (shapes.length !== 1) {
+    // only single elements can be attached
+    // multiply elements can be detached
+    if (newHost && shapes.length !== 1) {
       return;
     }
 
     if (newHost) {
-
       attachers = shapes;
     } else {
 
-      attachers = filter(shapes, function(s) {
-        return !!s.host;
+      // find attachers moved without host
+      attachers = filter(shapes, function(shape) {
+        var host = shape.host;
+
+        return isAttacher(shape) && !includes(shapes, host);
       });
     }
 
@@ -353,3 +356,11 @@ function removeAttached(elements) {
     return true;
   });
 }
+
+function isAttacher(shape) {
+  return !!shape.host;
+}
+
+function includes(array, item) {
+  return array.indexOf(item) !== -1;
+}
\ No newline at end of file
diff --git a/test/spec/features/attach-support/AttachSupportSpec.js b/test/spec/features/attach-support/AttachSupportSpec.js
index 56a384f27..bebb1fdd5 100644
--- a/test/spec/features/attach-support/AttachSupportSpec.js
+++ b/test/spec/features/attach-support/AttachSupportSpec.js
@@ -235,7 +235,7 @@ describe('features/attach-support', function() {
 
     var host, host2, attacher, attacher2;
 
-    beforeEach(inject(function(canvas, modeling, elementFactory, elementRegistry) {
+    beforeEach(inject(function(canvas, elementFactory) {
       host = elementFactory.createShape({
         id: 'host',
         x: 500, y: 100, width: 100, height: 100
@@ -404,7 +404,7 @@ describe('features/attach-support', function() {
 
 
     it('should move attachers along with parent', inject(
-      function(move, dragging, elementRegistry, selection) {
+      function(move, dragging, elementRegistry) {
 
         // given
         var rootGfx = elementRegistry.getGraphics(rootShape);
@@ -466,7 +466,7 @@ describe('features/attach-support', function() {
 
 
     it('should detach attacher from host', inject(
-      function(move, dragging, elementRegistry, eventBus) {
+      function(move, dragging, elementRegistry) {
 
         // given
         var parentGfx = elementRegistry.getGraphics(parentShape);
@@ -495,8 +495,41 @@ describe('features/attach-support', function() {
     ));
 
 
+    it('should detach multiple attachers from host', inject(
+      function(dragging, elementRegistry, move, selection) {
+
+        // given
+        var rootGfx = elementRegistry.getGraphics(rootShape);
+
+        selection.select([ attacher, attacher2 ]);
+
+        // when
+        move.start(canvasEvent({ x: 625, y: 125 }), attacher);
+
+        dragging.hover({
+          element: rootShape,
+          gfx: rootGfx
+        });
+
+        dragging.move(canvasEvent({ x: 725, y: 125 }));
+
+        dragging.end();
+
+        // then
+        expect(attacher.host).not.to.exist;
+        expect(attacher.parent).to.equal(rootShape);
+
+        expect(attacher2.host).not.to.exist;
+        expect(attacher2.parent).to.equal(rootShape);
+
+        expect(host.attachers).not.to.include(attacher);
+        expect(host.attachers).not.to.include(attacher2);
+      }
+    ));
+
+
     it('should reattach to host -> detachment (undo)', inject(
-      function(move, dragging, elementRegistry, eventBus, commandStack) {
+      function(move, dragging, elementRegistry, commandStack) {
 
         // given
         var parentGfx = elementRegistry.getGraphics(parentShape);