From e34359b9210e5fe78d45ad1845efe95d72e0b9c0 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 20 May 2024 18:56:48 +0200
Subject: [PATCH] VST3: skip context info callbacks during session load

This fixes a crash when SSL's channelstrip calls set-selection
early on during session load, during Session::load_routes.

Session::add_routes_inner calls calls ARDOUR::GUIIdle() which
can trigger a SSL Native Channel Strip 2" VST3 to call
VST3PI::setContextInfoValue, which in turn emits a
CoreSelection::send_selection_change before the session is
fully loaded.

This also handles various edge cases where a given AC may
not [yet] exist.
---
 libs/ardour/vst3_plugin.cc | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index d9f6227fa9..313751f659 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -2969,14 +2969,21 @@ VST3PI::getContextInfoValue (double& value, FIDString id)
 tresult
 VST3PI::setContextInfoValue (FIDString id, double value)
 {
-	if (!_owner) {
+	Stripable* s = dynamic_cast<Stripable*> (_owner);
+	if (!s) {
 		DEBUG_TRACE (DEBUG::VST3Callbacks, "VST3PI::setContextInfoValue<double>: not initialized");
 		return kNotInitialized;
 	}
 	DEBUG_TRACE (DEBUG::VST3Callbacks, string_compose ("VST3PI::setContextInfoValue<double> %1 to %2\n", id, value));
+	if (s->session ().loading () || s->session ().deletion_in_progress ()) {
+		return kResultOk;
+	}
 	if (0 == strcmp (id, ContextInfo::kVolume)) {
 		std::shared_ptr<AutomationControl> ac = lookup_ac (_owner, id);
-		ac->set_value (value, Controllable::NoGroup);
+		assert (ac);
+		if (ac) {
+			ac->set_value (value, Controllable::NoGroup);
+		}
 	} else if (0 == strcmp (id, ContextInfo::kPan)) {
 		std::shared_ptr<AutomationControl> ac = lookup_ac (_owner, id);
 		if (ac) {
@@ -3005,6 +3012,9 @@ VST3PI::setContextInfoValue (FIDString id, int32 value)
 		return kNotInitialized;
 	}
 	DEBUG_TRACE (DEBUG::VST3Callbacks, string_compose ("VST3PI::setContextInfoValue<int> %1 to %2\n", id, value));
+	if (s->session ().loading () || s->session ().deletion_in_progress ()) {
+		return kResultOk;
+	}
 	if (0 == strcmp (id, ContextInfo::kColor)) {
 #if BYTEORDER == kBigEndian
 		SWAP_32 (value) // ABGR32 -> RGBA32
@@ -3022,10 +3032,11 @@ VST3PI::setContextInfoValue (FIDString id, int32 value)
 		}
 	} else if (0 == strcmp (id, ContextInfo::kMultiSelect)) {
 		_add_to_selection = value != 0;
-	} else if (0 == strcmp (id, ContextInfo::kMute)) {
-		s->session ().set_control (lookup_ac (_owner, id), value != 0 ? 1 : 0, Controllable::NoGroup);
-	} else if (0 == strcmp (id, ContextInfo::kSolo)) {
-		s->session ().set_control (lookup_ac (_owner, id), value != 0 ? 1 : 0, Controllable::NoGroup);
+	} else if (0 == strcmp (id, ContextInfo::kMute) || 0 == strcmp (id, ContextInfo::kSolo)) {
+		std::shared_ptr<AutomationControl> ac = lookup_ac (_owner, id);
+		if (ac) {
+			s->session ().set_control (ac, value != 0 ? 1 : 0, Controllable::NoGroup);
+		}
 	} else {
 		DEBUG_TRACE (DEBUG::VST3Callbacks, "VST3PI::setContextInfoValue<int>: unsupported ID\n");
 		return kNotImplemented;