From fe43c733f8dbe193298915729f58abe848ab92d9 Mon Sep 17 00:00:00 2001
From: Alexander Ivash <elderorb@gmail.com>
Date: Sat, 17 Nov 2018 22:56:59 +0530
Subject: [PATCH 1/2] FB19400 during shutdown -- TypeError: Cannot read
 property 'buttons'

---
 interface/resources/qml/hifi/Desktop.qml           | 4 ++--
 interface/resources/qml/hifi/tablet/TabletHome.qml | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/interface/resources/qml/hifi/Desktop.qml b/interface/resources/qml/hifi/Desktop.qml
index f57c612b98..354c8095a0 100644
--- a/interface/resources/qml/hifi/Desktop.qml
+++ b/interface/resources/qml/hifi/Desktop.qml
@@ -70,8 +70,8 @@ OriginalDesktop.Desktop {
         anchors.horizontalCenter: settings.constrainToolbarToCenterX ? desktop.horizontalCenter : undefined;
         // Literal 50 is overwritten by settings from previous session, and sysToolbar.x comes from settings when not constrained.
         x: sysToolbar.x
-        buttonModel: tablet.buttons;
-        shown: tablet.toolbarMode;
+        buttonModel: tablet ? tablet.buttons : null;
+        shown: tablet ? tablet.toolbarMode : false;
     }
 
     Settings {
diff --git a/interface/resources/qml/hifi/tablet/TabletHome.qml b/interface/resources/qml/hifi/tablet/TabletHome.qml
index f1f54e8419..cbfb3c1337 100644
--- a/interface/resources/qml/hifi/tablet/TabletHome.qml
+++ b/interface/resources/qml/hifi/tablet/TabletHome.qml
@@ -115,9 +115,9 @@ Item {
             property int previousIndex: -1
             Repeater {
                 id: pageRepeater
-                model: Math.ceil(tabletProxy.buttons.rowCount() / TabletEnums.ButtonsOnPage)
+                model: tabletProxy != null ? Math.ceil(tabletProxy.buttons.rowCount() / TabletEnums.ButtonsOnPage) : 0
                 onItemAdded: {
-                    item.proxyModel.sourceModel = tabletProxy.buttons;
+                    item.proxyModel.sourceModel = tabletProxy != null ? tabletProxy.buttons : null;
                     item.proxyModel.pageIndex = index;
                 }
 

From 64d05e33c11b8b957630b26ebd7ddfdbe8451d04 Mon Sep 17 00:00:00 2001
From: Alexander Ivash <elderorb@gmail.com>
Date: Sun, 18 Nov 2018 00:24:45 +0530
Subject: [PATCH 2/2] second attempt to fix all other shutdown QML warnings at
 once

---
 libraries/qml/src/qml/OffscreenSurface.cpp  |  4 ++++
 libraries/qml/src/qml/impl/SharedObject.cpp | 15 +++++++++++++++
 libraries/qml/src/qml/impl/SharedObject.h   |  4 +++-
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/libraries/qml/src/qml/OffscreenSurface.cpp b/libraries/qml/src/qml/OffscreenSurface.cpp
index 91532534e3..abab5391e2 100644
--- a/libraries/qml/src/qml/OffscreenSurface.cpp
+++ b/libraries/qml/src/qml/OffscreenSurface.cpp
@@ -389,6 +389,10 @@ void OffscreenSurface::finishQmlLoad(QQmlComponent* qmlComponent,
         }
         // Allow child windows to be destroyed from JS
         QQmlEngine::setObjectOwnership(newObject, QQmlEngine::JavaScriptOwnership);
+
+        // add object to the manual deletion list
+        _sharedObject->addToDeletionList(newObject);
+
         newObject->setParent(parent);
         newItem->setParentItem(parent);
     } else {
diff --git a/libraries/qml/src/qml/impl/SharedObject.cpp b/libraries/qml/src/qml/impl/SharedObject.cpp
index 259defdb48..5bcca0821f 100644
--- a/libraries/qml/src/qml/impl/SharedObject.cpp
+++ b/libraries/qml/src/qml/impl/SharedObject.cpp
@@ -15,6 +15,7 @@
 #include <QtQml/QQmlEngine>
 
 #include <QtGui/QOpenGLContext>
+#include <QPointer>
 
 #include <NumericalConstants.h>
 #include <shared/NsightHelpers.h>
@@ -96,6 +97,15 @@ SharedObject::~SharedObject() {
     }
 #endif
 
+    // already deleted objects will be reset to null by QPointer so it should be safe just iterate here
+    for (auto qmlObject : _deletionList) {
+        if (qmlObject) {
+            // manually delete not-deleted-yet qml items
+            QQmlEngine::setObjectOwnership(qmlObject, QQmlEngine::CppOwnership);
+            delete qmlObject;
+        }
+    }
+
     if (_rootItem) {
         delete _rootItem;
         _rootItem = nullptr;
@@ -412,6 +422,11 @@ bool SharedObject::fetchTexture(TextureAndFence& textureAndFence) {
     return true;
 }
 
+void hifi::qml::impl::SharedObject::addToDeletionList(QObject * object)
+{
+    _deletionList.append(QPointer<QObject>(object));
+}
+
 void SharedObject::setProxyWindow(QWindow* window) {
 #ifndef DISABLE_QML
     _proxyWindow = window;
diff --git a/libraries/qml/src/qml/impl/SharedObject.h b/libraries/qml/src/qml/impl/SharedObject.h
index 002679c44d..ce9fcd46d2 100644
--- a/libraries/qml/src/qml/impl/SharedObject.h
+++ b/libraries/qml/src/qml/impl/SharedObject.h
@@ -66,7 +66,7 @@ public:
     void resume();
     bool isPaused() const;
     bool fetchTexture(TextureAndFence& textureAndFence);
-
+    void addToDeletionList(QObject* object);
 
 private:
     bool event(QEvent* e) override;
@@ -91,6 +91,8 @@ private:
     void onAboutToQuit();
     void updateTextureAndFence(const TextureAndFence& newTextureAndFence);
 
+    QList<QPointer<QObject>> _deletionList;
+
     // Texture management
     TextureAndFence _latestTextureAndFence{ 0, 0 };
     QQuickItem* _item{ nullptr };