From b744491dd2b524463a7a318a1635af5dd98510b2 Mon Sep 17 00:00:00 2001
From: Nick O'Leary <nick.oleary@gmail.com>
Date: Wed, 27 Apr 2016 10:31:19 +0100
Subject: [PATCH] Ensure config nodes are instantiated in the right order

---
 red/runtime/nodes/flows/Flow.js           | 33 +++++++++++--
 test/red/runtime/nodes/flows/Flow_spec.js | 57 ++++++++++++++++++++++-
 2 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/red/runtime/nodes/flows/Flow.js b/red/runtime/nodes/flows/Flow.js
index edeea1943..72b42eaf3 100644
--- a/red/runtime/nodes/flows/Flow.js
+++ b/red/runtime/nodes/flows/Flow.js
@@ -36,17 +36,40 @@ function Flow(global,flow) {
         var id;
         catchNodeMap = {};
         statusNodeMap = {};
-        for (id in flow.configs) {
-            if (flow.configs.hasOwnProperty(id)) {
-                node = flow.configs[id];
-                if (!activeNodes[id]) {
+
+        var configNodes = Object.keys(flow.configs);
+        var configNodeAttempts = {};
+        while(configNodes.length > 0) {
+            id = configNodes.shift();
+            node = flow.configs[id];
+            if (!activeNodes[id]) {
+                var readyToCreate = true;
+                // This node doesn't exist.
+                // Check it doesn't reference another non-existent config node
+                for (var prop in node) {
+                    if (node.hasOwnProperty(prop) && prop !== 'id' && prop !== 'wires' && prop !== '_users' && flow.configs[node[prop]]) {
+                        if (!activeNodes[node[prop]]) {
+                            // References a non-existent config node
+                            // Add it to the back of the list to try again later
+                            configNodes.push(id);
+                            configNodeAttempts[id] = (configNodeAttempts[id]||0)+1;
+                            if (configNodeAttempts[id] === 100) {
+                                throw new Error("Circular config node dependency detected: "+id);
+                            }
+                            readyToCreate = false;
+                            break;
+                        }
+                    }
+                }
+                if (readyToCreate) {
                     newNode = createNode(node.type,node);
                     if (newNode) {
                         activeNodes[id] = newNode;
                     }
                 }
             }
-        }
+        };
+
         if (diff && diff.rewired) {
             for (var j=0;j<diff.rewired.length;j++) {
                 var rewireNode = activeNodes[diff.rewired[j]];
diff --git a/test/red/runtime/nodes/flows/Flow_spec.js b/test/red/runtime/nodes/flows/Flow_spec.js
index 424ebc937..20a0a34cc 100644
--- a/test/red/runtime/nodes/flows/Flow_spec.js
+++ b/test/red/runtime/nodes/flows/Flow_spec.js
@@ -45,7 +45,7 @@ describe('Flow', function() {
 
     var TestNode = function(n) {
         Node.call(this,n);
-        createCount++;
+        this._index = createCount++;
         this.scope = n.scope;
         var node = this;
         this.foo = n.foo;
@@ -173,6 +173,61 @@ describe('Flow', function() {
         });
 
 
+        it("instantiates config nodes in the right order",function(done) {
+            var config = flowUtils.parseConfig([
+                {id:"t1",type:"tab"},
+                {id:"1",x:10,y:10,z:"t1",type:"test",foo:"a",wires:["2"]},
+                {id:"2",x:10,y:10,z:"t1",type:"test",foo:"a",wires:["3"]},
+                {id:"3",x:10,y:10,z:"t1",type:"test",foo:"a",wires:[]},
+                {id:"4",z:"t1",type:"test",foo:"5"}, // This node depends on #5
+                {id:"5",z:"t1",type:"test"}
+            ]);
+            var flow = Flow.create(config,config.flows["t1"]);
+            flow.start();
+
+            Object.keys(flow.getActiveNodes()).should.have.length(5);
+
+
+            currentNodes.should.have.a.property("1");
+            currentNodes.should.have.a.property("2");
+            currentNodes.should.have.a.property("3");
+            currentNodes.should.have.a.property("4");
+            currentNodes.should.have.a.property("5");
+
+            currentNodes["1"].should.have.a.property("_index",2);
+            currentNodes["2"].should.have.a.property("_index",3);
+            currentNodes["3"].should.have.a.property("_index",4);
+            currentNodes["4"].should.have.a.property("_index",1);
+            currentNodes["5"].should.have.a.property("_index",0);
+
+            flow.stop().then(function() {
+                currentNodes.should.not.have.a.property("1");
+                currentNodes.should.not.have.a.property("2");
+                currentNodes.should.not.have.a.property("3");
+                currentNodes.should.not.have.a.property("4");
+                currentNodes.should.not.have.a.property("5");
+                stoppedNodes.should.have.a.property("1");
+                stoppedNodes.should.have.a.property("2");
+                stoppedNodes.should.have.a.property("3");
+                stoppedNodes.should.have.a.property("4");
+                stoppedNodes.should.have.a.property("5");
+                done();
+            });
+        });
+
+
+        it("detects dependency loops in config nodes",function() {
+            var config = flowUtils.parseConfig([
+                {id:"t1",type:"tab"},
+                {id:"node1",z:"t1",type:"test",foo:"node2"}, // This node depends on #5
+                {id:"node2",z:"t1",type:"test",foo:"node1"}
+            ]);
+            var flow = Flow.create(config,config.flows["t1"]);
+            /*jshint immed: false */
+            (function(){
+                flow.start();
+            }).should.throw("Circular config node dependency detected: node1");
+        });
         it("instantiates a subflow and stops it",function(done) {
             var config = flowUtils.parseConfig([
                 {id:"t1",type:"tab"},