Fix crash when changing automation mode for MIDI track control automation.

Also some work towards tolerating automation controls with no automation list,
towards actually doing something for these cases, though not required just to
fix this crash (MidiTrack::set_parameter_automation_state() avoids those
paths).

4 files changed, 31 insertions, 6 deletions

diff --git a/libs/ardour/ardour/midi_track.h b/libs/ardour/ardour/midi_track.h
index 1acec0346e..cea3af5aed 100644
--- a/libs/ardour/ardour/midi_track.h
+++ b/libs/ardour/ardour/midi_track.h
@@ -93,6 +93,8 @@ public:
 		MidiTrack* _route;
 	};
 
+	virtual void set_parameter_automation_state (Evoral::Parameter param, AutoState);
+
 	NoteMode note_mode() const { return _note_mode; }
 	void set_note_mode (NoteMode m);
 
diff --git a/libs/ardour/automatable.cc b/libs/ardour/automatable.cc
index 7669f22df1..8629722889 100644
--- a/libs/ardour/automatable.cc
+++ b/libs/ardour/automatable.cc
@@ -137,16 +137,20 @@ Automatable::add_control(boost::shared_ptr<Evoral::Control> ac)
 	Evoral::Parameter param = ac->parameter();
 
 	boost::shared_ptr<AutomationList> al = boost::dynamic_pointer_cast<AutomationList> (ac->list ());
-	assert (al);
 
-	al->automation_state_changed.connect_same_thread (
-		_list_connections, boost::bind (&Automatable::automation_list_automation_state_changed, this, ac->parameter(), _1)
-		);
+	if (al) {
+		al->automation_state_changed.connect_same_thread (
+			_list_connections,
+			boost::bind (&Automatable::automation_list_automation_state_changed,
+			             this, ac->parameter(), _1));
+	}
 
 	ControlSet::add_control (ac);
 	_can_automate_list.insert (param);
 
-	automation_list_automation_state_changed (param, al->automation_state ()); // sync everything up
+	if (al) {
+		automation_list_automation_state_changed (param, al->automation_state ()); // sync everything up
+	}
 }
 
 string
@@ -394,6 +398,7 @@ Automatable::control_factory(const Evoral::Parameter& param)
 		MidiTrack* mt = dynamic_cast<MidiTrack*>(this);
 		if (mt) {
 			control = new MidiTrack::MidiControl(mt, param);
+			list.reset();  // No list, this is region "automation"
 		} else {
 			warning << "MidiCCAutomation for non-MidiTrack" << endl;
 		}
diff --git a/libs/ardour/automation_control.cc b/libs/ardour/automation_control.cc
index 355b0176ce..2bb694c7e5 100644
--- a/libs/ardour/automation_control.cc
+++ b/libs/ardour/automation_control.cc
@@ -85,7 +85,7 @@ AutomationControl::set_list (boost::shared_ptr<Evoral::ControlList> list)
 void
 AutomationControl::set_automation_state (AutoState as)
 {
-	if (as != alist()->automation_state()) {
+	if (_list && as != alist()->automation_state()) {
 
 		alist()->set_automation_state (as);
 
diff --git a/libs/ardour/midi_track.cc b/libs/ardour/midi_track.cc
index 638ed05706..3866eb4d80 100644
--- a/libs/ardour/midi_track.cc
+++ b/libs/ardour/midi_track.cc
@@ -623,6 +623,24 @@ MidiTrack::write_immediate_event(size_t size, const uint8_t* buf)
 }
 
 void
+MidiTrack::set_parameter_automation_state (Evoral::Parameter param, AutoState state)
+{
+	switch (param.type()) {
+	case MidiCCAutomation:
+	case MidiPgmChangeAutomation:
+	case MidiPitchBenderAutomation:
+	case MidiChannelPressureAutomation:
+	case MidiSystemExclusiveAutomation:
+		/* The track control for MIDI parameters is for immediate events to act
+		   as a control surface, write/touch for them is not currently
+		   supported. */
+		return;
+	default:
+		Automatable::set_parameter_automation_state(param, state);
+	}
+}
+
+void
 MidiTrack::MidiControl::set_value(double val)
 {
 	bool valid = false;