From c938c595c017147b9210b6a0b03d0e891cfb05bb Mon Sep 17 00:00:00 2001
From: Simon Walton <simon@highfidelity.io>
Date: Wed, 10 Oct 2018 17:11:42 -0700
Subject: [PATCH] Detect failed conversion from QVariant to JSON better

---
 libraries/octree/src/Octree.cpp | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libraries/octree/src/Octree.cpp b/libraries/octree/src/Octree.cpp
index 3d387e0956..37dd4e410f 100644
--- a/libraries/octree/src/Octree.cpp
+++ b/libraries/octree/src/Octree.cpp
@@ -878,14 +878,24 @@ bool Octree::toJSONDocument(QJsonDocument* doc, const OctreeElementPointer& elem
         return false;
     }
 
-    *doc = QJsonDocument::fromVariant(entityDescription);
+
+    bool noEntities = entityDescription["Entities"].toList().empty();
+    QJsonDocument jsonDocTree = QJsonDocument::fromVariant(entityDescription);
+    QJsonValue entitiesJson = jsonDocTree["Entities"];
+    if (entitiesJson.isNull() || (entitiesJson.toArray().empty() && !noEntities)) {
+        // Json version of entities too large.
+        return false;
+    } else {
+        *doc = jsonDocTree;
+    }
+
     return true;
 }
 
 bool Octree::toJSON(QByteArray* data, const OctreeElementPointer& element, bool doGzip) {
     QJsonDocument doc;
     if (!toJSONDocument(&doc, element)) {
-        qCritical("Failed to convert Entities to QVariantMap while converting to json.");
+        qCritical("Failed to convert Entities to JSON document.");
         return false;
     }