From 55b4784a02969adbe4d7f4ae0ae44af41c720d9f Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Wed, 22 Jul 2015 13:52:49 -0700
Subject: [PATCH] avoid entity-server node/octree deadlock on shutdown

---
 assignment-client/src/octree/OctreeSendThread.h |  2 +-
 assignment-client/src/octree/OctreeServer.cpp   | 17 +++++++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/assignment-client/src/octree/OctreeSendThread.h b/assignment-client/src/octree/OctreeSendThread.h
index 78f480b5eb..f22d63611c 100644
--- a/assignment-client/src/octree/OctreeSendThread.h
+++ b/assignment-client/src/octree/OctreeSendThread.h
@@ -42,7 +42,7 @@ protected:
     virtual bool process();
 
 private:
-    OctreeServer* _myServer;
+    QPointer<OctreeServer> _myServer;
     SharedNodePointer _node;
     QUuid _nodeUUID;
 
diff --git a/assignment-client/src/octree/OctreeServer.cpp b/assignment-client/src/octree/OctreeServer.cpp
index f5d599b5d3..c018d65f98 100644
--- a/assignment-client/src/octree/OctreeServer.cpp
+++ b/assignment-client/src/octree/OctreeServer.cpp
@@ -1175,13 +1175,22 @@ void OctreeServer::aboutToFinish() {
     if (_jurisdictionSender) {
         _jurisdictionSender->terminating();
     }
+    
+    QSet<SharedNodePointer> nodesToKill;
 
-    // force a shutdown of all of our OctreeSendThreads - at this point it has to be impossible for a
-    // linkedDataCreateCallback to be called for a new node
-    nodeList->eachNode([this](const SharedNodePointer& node) {
+    // Force a shutdown of all of our OctreeSendThreads.
+    // At this point it has to be impossible for a linkedDataCreateCallback to be called for a new node
+    nodeList->eachNode([&nodesToKill](const SharedNodePointer& node) {
+        nodesToKill << node;
+    });
+    
+    // What follows is a hack to force OctreeSendThreads to cleanup before the OctreeServer is gone.
+    // I would prefer to allow the SharedNodePointer ref count drop to zero to do this automatically
+    // but that isn't possible as long as the OctreeSendThread has an OctreeServer* that it uses.
+    for (auto& node : nodesToKill) {
         qDebug() << qPrintable(_safeServerName) << "server about to finish while node still connected node:" << *node;
         forceNodeShutdown(node);
-    });
+    }
 
     if (_persistThread) {
         _persistThread->aboutToFinish();