From fc64b13fe831739a7d16215f0843e7d02f0bac2b Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Wed, 10 Apr 2024 21:41:29 -0400
Subject: [PATCH] Clear engine before instantiating modules and before locking
 in Engine::fromJson(). Fixes ParamHandles from being removed immediately
 after instantiated modules add them.

---
 src/engine/Engine.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 68b1c09c..b01cbcf1 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -1215,7 +1215,11 @@ json_t* Engine::toJson() {
 
 
 void Engine::fromJson(json_t* rootJ) {
+	clear();
+
 	// modules
+	// We can't instantiate modules before clearing because some modules add ParamHandles upon construction.
+	// We also can't lock while instantiating modules because they call addParamHandle() which locks.
 	std::vector<Module*> modules;
 	json_t* modulesJ = json_object_get(rootJ, "modules");
 	if (!modulesJ)
@@ -1257,8 +1261,6 @@ void Engine::fromJson(json_t* rootJ) {
 
 	std::lock_guard<SharedMutex> lock(internal->mutex);
 
-	clear_NoLock();
-
 	// Add modules
 	for (Module* module : modules) {
 		addModule_NoLock(module);