From 570486d8c01eca68c13ace1aeb572d57adb1e108 Mon Sep 17 00:00:00 2001
From: aparajit-pratap <aparajit.pratap@autodesk.com>
Date: Mon, 26 Nov 2018 12:27:57 -0500
Subject: [PATCH] Fix crash with incorrect syntax in CBN in custom node (#9258)

* fix crash with cbn in custom node

* add recorded test

* add test description
---
 .../Engine/CodeGeneration/AstBuilder.cs       |  2 +-
 test/DynamoCoreWpfTests/RecordedTests.cs      | 14 ++++++++
 .../recorded/CreateCustomNodeSyntaxError.xml  | 32 +++++++++++++++++++
 3 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 test/core/recorded/CreateCustomNodeSyntaxError.xml

diff --git a/src/DynamoCore/Engine/CodeGeneration/AstBuilder.cs b/src/DynamoCore/Engine/CodeGeneration/AstBuilder.cs
index 0a6a2447564..4b828b98ce0 100644
--- a/src/DynamoCore/Engine/CodeGeneration/AstBuilder.cs
+++ b/src/DynamoCore/Engine/CodeGeneration/AstBuilder.cs
@@ -472,7 +472,7 @@ internal void CompileCustomNodeDefinition(
             else
             {
                 // For single output, directly return that identifier or null.
-                AssociativeNode returnValue = outputs.Count == 1 ? outputs[0] : new NullNode();
+                AssociativeNode returnValue = outputs.Count == 1 && outputs[0] != null ? outputs[0] : new NullNode();
                 functionBody.Body.Add(AstFactory.BuildReturnStatement(returnValue));
             }
 
diff --git a/test/DynamoCoreWpfTests/RecordedTests.cs b/test/DynamoCoreWpfTests/RecordedTests.cs
index 5c2e460fa7d..d8de0f9f044 100644
--- a/test/DynamoCoreWpfTests/RecordedTests.cs
+++ b/test/DynamoCoreWpfTests/RecordedTests.cs
@@ -709,6 +709,20 @@ public void TestCustomNode()
             AssertPreviewValue("04f6dab5-0a0b-4563-9f20-d0e58fcae7a5", 1.0);
         }
 
+        [Test]
+        public void TestCustomNodeSyntaxError_DoesNotCrash()
+        {
+            //Create custom node
+            //Scenario:
+            //1. Create custom node 
+            //2. Create code block node
+            //3. Type in a range expression (1..10) and commit the node
+            //4. Update the code block by introducing syntax error like "1...10"
+            //5. Test for crash
+            Assert.DoesNotThrow(() => RunCommandsFromFile("CreateCustomNodeSyntaxError.xml"));
+        }
+
+
         [Test]
         public void TestCustomNodeUI()
         {
diff --git a/test/core/recorded/CreateCustomNodeSyntaxError.xml b/test/core/recorded/CreateCustomNodeSyntaxError.xml
new file mode 100644
index 00000000000..80b3c5bee68
--- /dev/null
+++ b/test/core/recorded/CreateCustomNodeSyntaxError.xml
@@ -0,0 +1,32 @@
+<Commands ExitAfterPlayback="true" PauseAfterPlaybackInMs="10" CommandIntervalInMs="20">
+  <SelectModelCommand Modifiers="0">
+    <ModelGuid>00000000-0000-0000-0000-000000000000</ModelGuid>
+  </SelectModelCommand>
+  <CreateCustomNodeCommand Name="fdg" Category="Fdsg" Description="fdgs" MakeCurrent="true">
+    <ModelGuid>0ebfb690-5ed7-4cc1-ac59-f797c3c330a2</ModelGuid>
+  </CreateCustomNodeCommand>
+  <SelectModelCommand Modifiers="0">
+    <ModelGuid>00000000-0000-0000-0000-000000000000</ModelGuid>
+  </SelectModelCommand>
+  <CreateNodeCommand X="357.333333333333" Y="231.333333333333" DefaultPosition="false" TransformCoordinates="true">
+    <ModelGuid>d826ffc3-759e-4eb6-968e-82c0fa0a13f2</ModelGuid>
+    <Dynamo.Graph.Nodes.CodeBlockNodeModel guid="d826ffc3-759e-4eb6-968e-82c0fa0a13f2" type="Dynamo.Graph.Nodes.CodeBlockNodeModel" nickname="Code Block" x="265" y="200" isVisible="true" lacing="Disabled" isSelectedInput="False" isSelectedOutput="False" IsFrozen="false" isPinned="false" CodeText="1...10;" ShouldFocus="false">
+      <OutPortInfo LineIndex="0" />
+    </Dynamo.Graph.Nodes.CodeBlockNodeModel>
+  </CreateNodeCommand>
+  <UpdateModelValueCommand Name="Code" Value="1...10" WorkspaceGuid="e6953cd6-586f-442f-845c-cd7d93dacbc6">
+    <ModelGuid>d826ffc3-759e-4eb6-968e-82c0fa0a13f2</ModelGuid>
+  </UpdateModelValueCommand>
+  <SelectModelCommand Modifiers="0">
+    <ModelGuid>00000000-0000-0000-0000-000000000000</ModelGuid>
+  </SelectModelCommand>
+  <UpdateModelValueCommand Name="Code" Value="1..10;" WorkspaceGuid="e6953cd6-586f-442f-845c-cd7d93dacbc6">
+    <ModelGuid>d826ffc3-759e-4eb6-968e-82c0fa0a13f2</ModelGuid>
+  </UpdateModelValueCommand>
+  <SelectModelCommand Modifiers="0">
+    <ModelGuid>00000000-0000-0000-0000-000000000000</ModelGuid>
+  </SelectModelCommand>
+  <UpdateModelValueCommand Name="Code" Value="1...10;" WorkspaceGuid="e6953cd6-586f-442f-845c-cd7d93dacbc6">
+    <ModelGuid>d826ffc3-759e-4eb6-968e-82c0fa0a13f2</ModelGuid>
+  </UpdateModelValueCommand>
+</Commands>
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