From 9ad15dabe13b458143ba2a0097b6617314fe9cbd Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Fri, 14 Jul 2017 09:22:22 -0400
Subject: [PATCH] Bug1683: crashes applying Nyquist effects to stereo tracks

---
 src/effects/Effect.cpp | 3 ++-
 src/effects/Effect.h   | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 00f52b2ab..f50dcf160 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -2020,7 +2020,8 @@ void Effect::CopyInputTracks(int trackType)
    mIMap.clear();
    mOMap.clear();
 
-   mOutputTracks = std::make_unique<TrackList>();
+   mOutputTracks = std::make_shared<TrackList>();
+   mOutputTracks->SetSelf(mOutputTracks);
    mOutputTracksType = trackType;
 
    //iterate over tracks of type trackType (All types if Track::All)
diff --git a/src/effects/Effect.h b/src/effects/Effect.h
index 484c9668f..35bf80f79 100644
--- a/src/effects/Effect.h
+++ b/src/effects/Effect.h
@@ -445,7 +445,7 @@ protected:
    double         mSampleRate;
    TrackFactory   *mFactory;
    TrackList *inputTracks() const { return mTracks; }
-   std::unique_ptr<TrackList> mOutputTracks; // used only if CopyInputTracks() is called.
+   std::shared_ptr<TrackList> mOutputTracks; // used only if CopyInputTracks() is called.
    double         mT0;
    double         mT1;
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING