From a52ee84aede53ff2cb5a3e667e4ef03df1fd3acb Mon Sep 17 00:00:00 2001
From: mvdbeek <m.vandenbeek@gmail.com>
Date: Wed, 19 Sep 2018 12:10:24 +0200
Subject: [PATCH] Drop invalid connections if type_source is unavailable

---
 .../mvc/workflow/workflow-connector.js        |  7 +++++-
 .../mvc/workflow/workflow-terminals.js        | 23 ++++++++++---------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/client/galaxy/scripts/mvc/workflow/workflow-connector.js b/client/galaxy/scripts/mvc/workflow/workflow-connector.js
index 21c9e92da6c..8ae6ed9cddb 100644
--- a/client/galaxy/scripts/mvc/workflow/workflow-connector.js
+++ b/client/galaxy/scripts/mvc/workflow/workflow-connector.js
@@ -1,3 +1,5 @@
+import * as Toastr from "libs/toastr";
+
 function Connector(handle1, handle2) {
     this.canvas = null;
     this.dragging = false;
@@ -30,8 +32,11 @@ $.extend(Connector.prototype, {
         }
         $(this.canvas).remove();
     },
-    destroyIfInvalid: function() {
+    destroyIfInvalid: function(warn) {
         if (this.handle1 && this.handle2 && !this.handle2.attachable(this.handle1)) {
+            if (warn) {
+                Toastr.warning("Destroying a connection because collection type has changed.");
+            }
             this.destroy();
         }
     },
diff --git a/client/galaxy/scripts/mvc/workflow/workflow-terminals.js b/client/galaxy/scripts/mvc/workflow/workflow-terminals.js
index 8bce14bafd6..f7504f728a3 100644
--- a/client/galaxy/scripts/mvc/workflow/workflow-terminals.js
+++ b/client/galaxy/scripts/mvc/workflow/workflow-terminals.js
@@ -1,6 +1,5 @@
 // TODO; tie into Galaxy state?
 window.workflow_globals = window.workflow_globals || {};
-import * as Toastr from "libs/toastr";
 
 function CollectionTypeDescription(collectionType) {
     this.collectionType = collectionType;
@@ -131,7 +130,9 @@ var Terminal = Backbone.Model.extend({
         if (this.node) {
             this.node.markChanged();
             this.resetMappingIfNeeded();
-            this.resetCollectionTypeSource();
+            if (!connector.dragging) {
+                this.resetCollectionTypeSource();
+            }
         }
     },
     redraw: function() {
@@ -181,9 +182,8 @@ var Terminal = Backbone.Model.extend({
         let node = this.node;
         _.each(node.output_terminals, function(output_terminal) {
             let type_source = output_terminal.attributes.collection_type_source;
-            if (type_source) {
+            if (type_source && output_terminal.attributes.collection_type) {
                 output_terminal.attributes.collection_type = null;
-                output_terminal.collectionType = ANY_COLLECTION_TYPE_DESCRIPTION;
                 output_terminal.update(output_terminal.attributes);
             }
         });
@@ -454,7 +454,7 @@ var InputCollectionTerminal = BaseInputTerminal.extend({
         } else {
             let node = this.node;
             _.each(node.output_terminals, function(output_terminal) {
-                if (output_terminal.attributes.collection_type_source) {
+                if (output_terminal.attributes.collection_type_source && !connector.dragging) {
                     output_terminal.attributes.collection_type = other.attributes.collection_type;
                     output_terminal.update(output_terminal.attributes);
                     }
@@ -544,14 +544,15 @@ var OutputCollectionTerminal = Terminal.extend({
             newCollectionType = ANY_COLLECTION_TYPE_DESCRIPTION;
         }
 
-        if (newCollectionType.collectionType != this.collectionType.collectionType) {
-            _.each(this.connectors, connector => {
-                // TODO: consider checking if connection valid before removing...
-                Toastr.warning("Destroying a connection because collection type has changed.");
-                connector.destroy();
+        let oldCollectionType = this.collectionType;
+        this.collectionType = newCollectionType;
+        // we need to iterate over a copy, as we slice this.connectors in the process of destroying connections
+        var connectors = this.connectors.slice(0);
+        if (newCollectionType.collectionType != oldCollectionType.collectionType) {
+            _.each(connectors, connector => {
+                connector.destroyIfInvalid(true);
             });
         }
-        this.collectionType = newCollectionType;
     }
 });