From 57c50ff9ac387da70b882b80b88c47f7503478a0 Mon Sep 17 00:00:00 2001
From: James Crook <james.k.crook@gmail.com>
Date: Wed, 14 Feb 2018 18:28:36 +0000
Subject: [PATCH] Nyquist can now make a selection and not have it overwritten
 by Effect.

---
 src/commands/SelectCommand.cpp  | 9 +++++++++
 src/effects/Effect.cpp          | 2 +-
 src/effects/Effect.h            | 2 ++
 src/effects/nyquist/Nyquist.cpp | 4 +++-
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/commands/SelectCommand.cpp b/src/commands/SelectCommand.cpp
index 1ac3cc849..d7e910620 100644
--- a/src/commands/SelectCommand.cpp
+++ b/src/commands/SelectCommand.cpp
@@ -61,6 +61,10 @@ bool SelectTimeCommand::Apply(const CommandContext & context){
    if( !bHasT0 && !bHasT1 )
       return true;
 
+   // Count selection as a do-nothing effect.
+   // Used to invalidate cached selection and tracks.
+   Effect::IncEffectCounter();
+
    if( mFromEnd ){
       double TEnd = context.GetProject()->GetTracks()->GetEndTime();
       context.GetProject()->mViewInfo.selectedRegion.setTimes(TEnd - mT0, TEnd - mT1);
@@ -110,6 +114,11 @@ bool SelectTracksCommand::Apply(const CommandContext &context)
 {
    if( !bHasFirstTrack && !bHasLastTrack )
       return true;
+
+   // Count selection as a do-nothing effect.
+   // Used to invalidate cached selection and tracks.
+   Effect::IncEffectCounter();
+
    int index = 0;
    TrackList *tracks = context.GetProject()->GetTracks();
    int last = wxMax( mFirstTrack, mLastTrack );
diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 3b9286c7e..a0b46e2cd 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -1266,7 +1266,7 @@ bool Effect::DoEffect(wxWindow *parent,
       returnVal = Process();
    }
 
-   if (returnVal)
+   if (returnVal && (mT1 >= mT0 ))
    {
       selectedRegion->setTimes(mT0, mT1);
    }
diff --git a/src/effects/Effect.h b/src/effects/Effect.h
index 867828d99..b876c874e 100644
--- a/src/effects/Effect.h
+++ b/src/effects/Effect.h
@@ -269,6 +269,8 @@ class AUDACITY_DLL_API Effect /* not final */ : public wxEvtHandler,
                   long style = DefaultMessageBoxStyle,
                   const wxString& titleStr = wxString{});
 
+   static void IncEffectCounter(){ nEffectsDone++;};
+
 //
 // protected virtual methods
 //
diff --git a/src/effects/nyquist/Nyquist.cpp b/src/effects/nyquist/Nyquist.cpp
index a16e5bc32..2b9cae792 100644
--- a/src/effects/nyquist/Nyquist.cpp
+++ b/src/effects/nyquist/Nyquist.cpp
@@ -859,8 +859,10 @@ _("Selection too long for Nyquist code.\nMaximum allowed selection is %ld sample
    // Has rug been pulled from under us by some effect done within Nyquist??
    if( nEffectsSoFar == nEffectsDone )
       ReplaceProcessedTracks(success);
-   else
+   else{
       ReplaceProcessedTracks(false); // Do not use the results.
+      mT1 = mT0 - 1.0;// And don't use the times either, in resetting the selection  (make them bogus).
+   }
 
    if (!mProjectChanged)
       em.SetSkipStateFlag(true);