Prevent crash when detaching freed debugger

Author: KoBeWi

editor/debugger/editor_debugger_plugin.cpp

@@ -109,7 +109,7 @@ void EditorDebuggerSession::set_breakpoint(const String &p_path, int p_line, boo
 }
 
 void EditorDebuggerSession::detach_debugger() {
-	if (!debugger) {
+	if (!debugger || !ObjectDB::get_instance(debugger_id)) {
 		return;
 	}
 	debugger->disconnect("started", callable_mp(this, &EditorDebuggerSession::_started));
@@ -125,6 +125,7 @@ void EditorDebuggerSession::detach_debugger() {
 EditorDebuggerSession::EditorDebuggerSession(ScriptEditorDebugger *p_debugger) {
 	ERR_FAIL_NULL(p_debugger);
 	debugger = p_debugger;
+	debugger_id = p_debugger->get_instance_id();
 	debugger->connect("started", callable_mp(this, &EditorDebuggerSession::_started));
 	debugger->connect("stopped", callable_mp(this, &EditorDebuggerSession::_stopped));
 	debugger->connect("breaked", callable_mp(this, &EditorDebuggerSession::_breaked));

editor/debugger/editor_debugger_plugin.h

@@ -43,6 +43,7 @@ class EditorDebuggerSession : public RefCounted {
 	HashSet<Control *> tabs;
 
 	ScriptEditorDebugger *debugger = nullptr;
+	ObjectID debugger_id;
 
 	void _breaked(bool p_really_did, bool p_can_debug, const String &p_message, bool p_has_stackdump);
 	void _started();