From 350938b68ea98f3bdfc702daf7a11aa10359b45f Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 14 Jan 2021 01:43:20 +0100
Subject: [PATCH] Fix crash at exit when EngineDialog shows some page other
 than 1st

#1  std::operator==<char> (__lhs=<error reading variable: Cannot access memory at address 0x801f0f1f>) at /usr/include/c++/8/bits/basic_string.h:6058
#2  EngineControl::get_matching_state at ../gtk2_ardour/engine_dialog.cc:1874
#3  EngineControl::get_saved_state_for_currently_displayed_backend_and_device() at ../gtk2_ardour/engine_dialog.cc:1893
#4  EngineControl::post_push() at ../gtk2_ardour/engine_dialog.cc:2655
#5  EngineControl::push_state_to_backend(bool) at ../gtk2_ardour/engine_dialog.cc:2643
#6  EngineControl::on_switch_page(_GtkNotebookPage*, unsigned int) (this=0x55bc43fd4d40, page_num=1) at ../gtk2_ardour/engine_dialog.cc:2988
[...]
#20  () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#21 g_object_run_dispose () at /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#22 Gtk::VBox::~VBox() () at /usr/lib/x86_64-linux-gnu/libgtkmm-2.4.so.1
#23 EngineControl::~EngineControl() (this=0x55bc43fd4d40, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at ../gtk2_ardour/engine_dialog.cc:73
---
 gtk2_ardour/engine_dialog.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index cb674227a7..7430d93211 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -2939,6 +2939,9 @@ EngineControl::set_desired_sample_rate (uint32_t sr)
 void
 EngineControl::on_switch_page (GtkNotebookPage*, guint page_num)
 {
+	if (ignore_changes) {
+		return;
+	}
 	if (page_num == 0) {
 		_measure_midi.reset();
 		update_sensitivity ();