From d8725ff3c8a984fb40ea787269e8d60bd71c4ae5 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 17 Aug 2024 05:29:04 +0200
Subject: [PATCH] RegionFX: fix crash when custom GUI thread sends change
 requests

This can happen with VST2s (e.g gvst) and some JUCE based plugins.
Previously that lead to a "programming error: no per-thread pool"
when the DR queues a overwrite buffer session-event.
---
 libs/ardour/audioregion.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 93262909c2..ddcaacadd5 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -47,6 +47,7 @@
 #include "ardour/analysis_graph.h"
 #include "ardour/audioregion.h"
 #include "ardour/buffer_manager.h"
+#include "ardour/butler.h"
 #include "ardour/session.h"
 #include "ardour/dB.h"
 #include "ardour/debug.h"
@@ -2350,7 +2351,12 @@ AudioRegion::_add_plugin (std::shared_ptr<RegionFxPlugin> rfx, std::shared_ptr<R
 						return;
 					}
 					if (!_invalidated.exchange (true)) {
-						send_change (PropertyChange (Properties::region_fx)); // trigger DiskReader overwrite
+					  /* catch changes from some custom plugin GUI threads (VST2, and JUCE) */
+						if (SessionEvent::has_per_thread_pool ()) {
+							send_change (PropertyChange (Properties::region_fx)); // trigger DiskReader overwrite
+						} else {
+							_session.butler ()->delegate (boost::bind (&AudioRegion::send_change, this, PropertyChange (Properties::region_fx)));
+						}
 					}
 				});
 		if (!ac->alist ()) {