From cf04c46a5ee86d239f820004b721e2f2729d0abe Mon Sep 17 00:00:00 2001
From: Haoyu Qiu <timothyqiu32@gmail.com>
Date: Tue, 28 Dec 2021 15:29:21 +0800
Subject: [PATCH] Clear pending function states when reloading GDScript

(cherry picked from commit 53af7ee48296d7e39547169574b8ec6f24ba38eb)
---
 modules/gdscript/gdscript.cpp | 21 +++++++++++++--------
 modules/gdscript/gdscript.h   |  1 +
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/modules/gdscript/gdscript.cpp b/modules/gdscript/gdscript.cpp
index 3a7e668dfdd..4ef8d178915 100644
--- a/modules/gdscript/gdscript.cpp
+++ b/modules/gdscript/gdscript.cpp
@@ -77,6 +77,17 @@ Object *GDScriptNativeClass::instance() {
 	return ClassDB::instance(name);
 }
 
+void GDScript::_clear_pending_func_states() {
+	GDScriptLanguage::get_singleton()->lock.lock();
+	while (SelfList<GDScriptFunctionState> *E = pending_func_states.first()) {
+		// Order matters since clearing the stack may already cause
+		// the GDSCriptFunctionState to be destroyed and thus removed from the list.
+		pending_func_states.remove(E);
+		E->self()->_clear_stack();
+	}
+	GDScriptLanguage::get_singleton()->lock.unlock();
+}
+
 GDScriptInstance *GDScript::_create_instance(const Variant **p_args, int p_argcount, Object *p_owner, bool p_isref, Variant::CallError &r_error) {
 	/* STEP 1, CREATE */
 
@@ -597,6 +608,7 @@ Error GDScript::reload(bool p_keep_state) {
 	for (Map<StringName, Ref<GDScript>>::Element *E = subclasses.front(); E; E = E->next()) {
 		_set_subclass_path(E->get(), path);
 	}
+	_clear_pending_func_states();
 
 	return OK;
 }
@@ -923,14 +935,7 @@ void GDScript::_save_orphaned_subclasses() {
 }
 
 GDScript::~GDScript() {
-	GDScriptLanguage::get_singleton()->lock.lock();
-	while (SelfList<GDScriptFunctionState> *E = pending_func_states.first()) {
-		// Order matters since clearing the stack may already cause
-		// the GDSCriptFunctionState to be destroyed and thus removed from the list.
-		pending_func_states.remove(E);
-		E->self()->_clear_stack();
-	}
-	GDScriptLanguage::get_singleton()->lock.unlock();
+	_clear_pending_func_states();
 
 	for (Map<StringName, GDScriptFunction *>::Element *E = member_functions.front(); E; E = E->next()) {
 		memdelete(E->get());
diff --git a/modules/gdscript/gdscript.h b/modules/gdscript/gdscript.h
index 026e0c3455e..476d8abd579 100644
--- a/modules/gdscript/gdscript.h
+++ b/modules/gdscript/gdscript.h
@@ -112,6 +112,7 @@ class GDScript : public Script {
 	SelfList<GDScript> script_list;
 
 	SelfList<GDScriptFunctionState>::List pending_func_states;
+	void _clear_pending_func_states();
 
 	GDScriptInstance *_create_instance(const Variant **p_args, int p_argcount, Object *p_owner, bool p_isref, Variant::CallError &r_error);