From 9d4f9b0a4b0a69a6603fffc7b5674e4d97c64790 Mon Sep 17 00:00:00 2001
From: humbletim <humbletim@gmail.com>
Date: Wed, 21 Jun 2017 16:00:47 -0400
Subject: [PATCH] more safeguards to help diagnose broken EventBridges

---
 .../marketplace/camera-move/app.html               | 14 +++++++++-----
 .../marketplace/camera-move/modules/_utils.js      |  5 ++++-
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/unpublishedScripts/marketplace/camera-move/app.html b/unpublishedScripts/marketplace/camera-move/app.html
index 00df8e7514..6ab439d58d 100644
--- a/unpublishedScripts/marketplace/camera-move/app.html
+++ b/unpublishedScripts/marketplace/camera-move/app.html
@@ -88,12 +88,16 @@ try {
         }
     });
 
-    function onEventBridgeOpened(eventBridge) {
-        EventBridge = eventBridge;
-        log('openEventBridge.opened', EventBridge);
+    function onEventBridgeOpened(_eventBridge) {
+        if (!window.EventBridge) {
+            window.EventBridge = _eventBridge;
+        }
+        assert(_eventBridge === window.EventBridge,
+               'ERROR: window.EventBridge materialized spontaneously and differently from the QWebChannel-derived value');
+        log('openEventBridge.opened', window.EventBridge);
 
         bridgedSettings = new BridgedSettings({
-            eventBridge: EventBridge,
+            eventBridge: window.EventBridge,
             namespace: PARAMS.namespace,
             uuid: PARAMS.uuid,
             debug: PARAMS.debug,
@@ -114,7 +118,7 @@ try {
 
         debugPrint('>>> SENDING ACK');
         // let Client script know we are ready
-        eventBridge.emitWebEvent(location.href);
+        bridgedSettings.eventBridge.emitWebEvent(location.href);
 
         function onValueReceived(key, value, oldValue, origin) {
             onMutationEvent.paused++;
diff --git a/unpublishedScripts/marketplace/camera-move/modules/_utils.js b/unpublishedScripts/marketplace/camera-move/modules/_utils.js
index 8e57e5b7cf..65314ef98e 100644
--- a/unpublishedScripts/marketplace/camera-move/modules/_utils.js
+++ b/unpublishedScripts/marketplace/camera-move/modules/_utils.js
@@ -239,12 +239,15 @@ function BrowserUtils(global) {
                 // this.log('openEventBridge| EventBridge already exists... -- invoking callback', 'typeof EventBridge == ' + typeof global.EventBridge);
                 return callback(global.EventBridge);
             } catch (e) {
-                this.log('EventBridge does not yet exist -- attempting to instrument via qt.webChannelTransport');
+                this.log('EventBridge does not yet exist in a usable state -- attempting to instrument via qt.webChannelTransport',
+                         Object.keys(global.EventBridge));
                 var QWebChannel = assert(global.QWebChannel, 'expected global.QWebChannel to exist'),
                     qt = assert(global.qt, 'expected global.qt to exist');
                 assert(qt.webChannelTransport, 'expected global.qt.webChannelTransport to exist');
                 new QWebChannel(qt.webChannelTransport, bind(this, function (channel) {
                     var objects = channel.objects;
+                    assert(!global.EventBridge, '... global.EventBridge was unavailable at page load, but has unexpectedly materialized; ' +
+                           Object.keys(global.EventBridge));
                     global.EventBridge = objects.eventBridge || (objects.eventBridgeWrapper && objects.eventBridgeWrapper.eventBridge);
                     assert(global.EventBridge, '!global.EventBridge');
                     global.EventBridge.$WebChannel = channel;