Fixed deadlock in Create App

cmake/modules/FindV8.cmake

@@ -264,6 +264,7 @@ find_library(V8_ICUI18N_LIBRARY_RELEASE
 MESSAGE("V8_ICUI18N_LIBRARY_RELEASE: ${V8_ICUI18N_LIBRARY_RELEASE}")
 
 # Base build with snapshot
+MESSAGE("1")
 if(MSVC)
 	if(V8_LIBRARY_DEBUG AND V8_LIBRARY_RELEASE AND V8_SNAPSHOT_LIBRARY_DEBUG AND V8_SNAPSHOT_LIBRARY_RELEASE)
 		set(V8_LIBRARY
@@ -280,10 +281,13 @@ if(MSVC)
 		)
 	endif()
 else()
-	if(CMAKE_BUILD_TYPE EQUAL "Debug")
+	MESSAGE("2")
+	if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+		MESSAGE("3")
 		if(V8_LIBRARY_DEBUG AND V8_PLATFORM_LIBRARY_DEBUG AND V8_SAMPLER_LIBRARY_DEBUG)
 			set(V8_LIBRARY ${V8_LIBRARY_DEBUG} ${V8_PLATFORM_LIBRARY_DEBUG} ${V8_SAMPLER_LIBRARY_DEBUG}) # ${V8_ICU_LIBRARY_DEBUG})
 		elseif(V8_LIBRARY_DEBUG AND V8_PLATFORM_LIBRARY_DEBUG)
+			MESSAGE("4")
 			set(V8_LIBRARY ${V8_LIBRARY_DEBUG} ${V8_PLATFORM_LIBRARY_DEBUG}) # ${V8_SAMPLER_LIBRARY_DEBUG}) # ${V8_ICU_LIBRARY_DEBUG})
 		else()
 			if(V8_LIBRARY_RELEASE AND V8_PLATFORM_LIBRARY_RELEASE AND V8_SAMPLER_LIBRARY_RELEASE)

libraries/entities/src/EntityScriptingInterface.cpp

@@ -21,6 +21,7 @@
 #include <QJsonObject>
 #include <QJsonDocument>
 #include <QJsonArray>
+#include <QtWidgets/QApplication>
 
 #include <shared/QtHelpers.h>
 #include <VariantMapToScriptValue.h>
@@ -1633,12 +1634,15 @@ bool EntityScriptingInterface::queryPropertyMetadata(const QUuid& entityID,
     }
 }
 
-bool EntityScriptingInterface::getServerScriptStatus(const QUuid& entityID, const ScriptValue& callback) {
+//bool EntityScriptingInterface::getServerScriptStatus(const QUuid& entityID, const ScriptValue& callback) {
+bool EntityScriptingInterface::getServerScriptStatus(const QUuid& entityID, ScriptValue callback) {
     auto client = DependencyManager::get<EntityScriptClient>();
     auto request = client->createScriptStatusRequest(entityID);
 
     auto engine = callback.engine();
     auto manager = engine->manager();
+    Q_ASSERT(QThread::currentThread() == engine->thread());
+    Q_ASSERT(QThread::currentThread() == engine->manager()->thread());
     if (!manager) {
         engine->raiseException(engine->makeError(engine->newValue("This script does not belong to a ScriptManager")));
         engine->maybeEmitUncaughtException(__FUNCTION__);
@@ -1647,13 +1651,16 @@ bool EntityScriptingInterface::getServerScriptStatus(const QUuid& entityID, cons
 
     connect(request, &GetScriptStatusRequest::finished, manager, [callback](GetScriptStatusRequest* request) mutable {
         auto engine = callback.engine();
-        // V8TODO: it seems to sometimes be called on a wrong thread, reading to script engine crashes. I added an assert for now
+        // V8TODO: it seems to sometimes be called on a wrong thread, reading to script engine crashes. I added an assert for now.
+        // V8TODO: somehow the asserts are not happening here, but destructor still runs on main thread sometimes and deadlocks.
         Q_ASSERT(QThread::currentThread() == engine->thread());
         Q_ASSERT(QThread::currentThread() == engine->manager()->thread());
         QString statusString = EntityScriptStatus_::valueToKey(request->getStatus());
         ScriptValueList args { engine->newValue(request->getResponseReceived()), engine->newValue(request->getIsRunning()), engine->newValue(statusString.toLower()), engine->newValue(request->getErrorInfo()) };
         callback.call(ScriptValue(), args);
         request->deleteLater();
+        // This causes ScriptValueProxy to be released, and thus its destructor is called on script engine thread and not main thread
+        callback = ScriptValue();
     });
     request->start();
     return true;

libraries/entities/src/EntityScriptingInterface.h

@@ -871,7 +871,8 @@ public slots:
      * @param {string} errorInfo - <code>""</code> if there is a server entity script running, otherwise it may contain extra 
      *     information on the error.
      */
-    Q_INVOKABLE bool getServerScriptStatus(const QUuid& entityID, const ScriptValue& callback);
+    //Q_INVOKABLE bool getServerScriptStatus(const QUuid& entityID, const ScriptValue& callback);
+    Q_INVOKABLE bool getServerScriptStatus(const QUuid& entityID, ScriptValue callback);
 
     /*@jsdoc
      * Gets metadata for certain entity properties such as <code>script</code> and <code>serverScripts</code>.

libraries/script-engine/src/v8/ScriptValueV8Wrapper.cpp

@@ -20,6 +20,8 @@
 
 
 void ScriptValueV8Wrapper::release() {
+    // V8TODO: maybe add an assert to check if it happens on script engine thread?
+    // With v8::Locker in V8ScriptValue such requirement shouldn't be necessary but deleting on different threadwww can cause deadlocks sometimes
     delete this;
 }