Fix crash when copying MIDI regions with midi-copy-is-fork is on (#6002).

4 files changed, 18 insertions, 2 deletions

diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index afb6430242..e009e0ef51 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -109,6 +109,9 @@ class LIBARDOUR_API Source : public SessionObject
 	bool used() const { return use_count() > 0; }
 	uint32_t level() const { return _level; }
 
+	std::string ancestor_name() { return _ancestor_name.empty() ? name() : _ancestor_name; }
+	void set_ancestor_name(const std::string& name) { _ancestor_name = name; }
+
   protected:
 	DataType            _type;
 	Flag                _flags;
@@ -119,6 +122,7 @@ class LIBARDOUR_API Source : public SessionObject
         mutable Glib::Threads::Mutex _analysis_lock;
 	gint                _use_count; /* atomic */
 	uint32_t            _level; /* how deeply nested is this source w.r.t a disk file */
+	std::string         _ancestor_name;
 
   private:
 	void fix_writable_flags ();
diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index e7298e7526..03db3eaaa7 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -133,6 +133,7 @@ MidiRegion::clone (string path) const
 	boost::shared_ptr<MidiSource> newsrc;
 
 	/* caller must check for pre-existing file */
+	assert (!path.empty());
 	assert (!Glib::file_test (path, Glib::FILE_TEST_EXISTS));
 	newsrc = boost::dynamic_pointer_cast<MidiSource>(
 		SourceFactory::createWritable(DataType::MIDI, _session,
diff --git a/libs/ardour/region_factory.cc b/libs/ardour/region_factory.cc
index 9654a4b3de..7c9f4fd228 100644
--- a/libs/ardour/region_factory.cc
+++ b/libs/ardour/region_factory.cc
@@ -19,6 +19,7 @@
 
 #include <inttypes.h>
 
+#include "pbd/basename.h"
 #include "pbd/error.h"
 
 #include "ardour/audioregion.h"
@@ -58,7 +59,17 @@ RegionFactory::create (boost::shared_ptr<const Region> region, bool announce)
 	} else if ((mr = boost::dynamic_pointer_cast<const MidiRegion>(region)) != 0) {
 
 		if (mr->session().config.get_midi_copy_is_fork()) {
-			ret = mr->clone ();
+			/* What we really want to do here is what Editor::fork_region()
+			   does via Session::create_midi_source_by_stealing_name(), but we
+			   don't have a Track.  We'll just live with the skipped number,
+			   and store the ancestral name of sources so multiple clones
+			   generates reasonable names that don't have too many suffixes. */
+			const std::string ancestor_name = mr->sources().front()->ancestor_name();
+			const std::string base          = PBD::basename_nosuffix(ancestor_name);
+
+			boost::shared_ptr<MidiSource> source = mr->session().create_midi_source_for_session(base);
+			source->set_ancestor_name(mr->sources().front()->name());
+			ret = mr->clone(source);
 		} else {
 			ret = boost::shared_ptr<Region> (new MidiRegion (mr, 0));
 		}
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 2878bb8014..9c5b6fdccf 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -3734,7 +3734,7 @@ Session::new_audio_source_path (const string& base, uint32_t nchan, uint32_t cha
 	return s;
 }
 
-/** Return a unique name based on \a owner_name for a new internal MIDI source */
+/** Return a unique name based on `base` for a new internal MIDI source */
 string
 Session::new_midi_source_path (const string& base)
 {