When opening a file into a new project, delete the project on failure

src/AudacityApp.cpp

@@ -831,13 +831,12 @@ bool AudacityApp::MRUOpen(const wxString &fullPathStr) {
          // there are no tracks, but there's an Undo history, etc, then
          // bad things can happen, including data files moving to the NEW
          // project directory, etc.
-         if (!proj || proj->GetDirty() || !proj->GetIsEmpty()) {
-            proj = CreateNewAudacityProject();
-         }
+         if (proj && (proj->GetDirty() || !proj->GetIsEmpty()))
+            proj = nullptr;
          // This project is clean; it's never been touched.  Therefore
          // all relevant member variables are in their initial state,
          // and it's okay to open a NEW project inside this window.
-         proj->OpenFile(fullPathStr);
+         AudacityProject::OpenProject( proj, fullPathStr );
       }
       else {
          // File doesn't exist - remove file from history

src/AutoRecovery.cpp

@@ -198,7 +198,6 @@ static bool RecoverAllProjects(AudacityProject** pproj)
 
    // Open a project window for each auto save file
    wxString filename;
-   AudacityProject* proj = NULL;
 
    wxArrayString files;
    wxDir::GetAllFiles(FileNames::AutoSaveDir(), &files,
@@ -206,21 +205,18 @@ static bool RecoverAllProjects(AudacityProject** pproj)
 
    for (unsigned int i = 0; i < files.GetCount(); i++)
    {
+      AudacityProject* proj{};
       if (*pproj)
       {
          // Reuse existing project window
          proj = *pproj;
          *pproj = NULL;
-      } else
-      {
-         // Create NEW project window
-         proj = CreateNewAudacityProject();
       }
 
       // Open project. When an auto-save file has been opened successfully,
       // the opened auto-save file is automatically deleted and a NEW one
       // is created.
-      proj->OpenFile(files[i], false);
+      AudacityProject::OpenProject( proj, files[i], false );
    }
 
    return true;

src/Menus.cpp

@@ -5865,26 +5865,36 @@ void AudacityProject::OnImportMIDI()
       gPrefs->Write(wxT("/DefaultOpenPath"), path);
       gPrefs->Flush();
 
-      DoImportMIDI(fileName);
+      AudacityProject::DoImportMIDI(this, fileName);
    }
 }
 
-void AudacityProject::DoImportMIDI(const wxString &fileName)
+AudacityProject *AudacityProject::DoImportMIDI(
+   AudacityProject *pProject, const wxString &fileName)
 {
-   auto newTrack = GetTrackFactory()->NewNoteTrack();
+   AudacityProject *pNewProject {};
+   if ( !pProject )
+      pProject = pNewProject = CreateNewAudacityProject();
+   auto cleanup = finally( [&] { if ( pNewProject ) pNewProject->Close(true); } );
+
+   auto newTrack = pProject->GetTrackFactory()->NewNoteTrack();
 
    if (::ImportMIDI(fileName, newTrack.get())) {
 
-      SelectNone();
-      auto pTrack = mTracks->Add(std::move(newTrack));
+      pProject->SelectNone();
+      auto pTrack = pProject->mTracks->Add(std::move(newTrack));
       pTrack->SetSelected(true);
 
-      PushState(wxString::Format(_("Imported MIDI from '%s'"),
+      pProject->PushState(wxString::Format(_("Imported MIDI from '%s'"),
          fileName.c_str()), _("Import MIDI"));
 
-      RedrawProject();
-      mTrackPanel->EnsureVisible(pTrack);
+      pProject->RedrawProject();
+      pProject->mTrackPanel->EnsureVisible(pTrack);
+      pNewProject = nullptr;
+      return pProject;
    }
+   else
+      return nullptr;
 }
 #endif // USE_MIDI
 

src/Menus.h

@@ -347,7 +347,12 @@ void OnRescanDevices();
 void OnImport();
 void OnImportLabels();
 void OnImportMIDI();
-void DoImportMIDI(const wxString &fileName);
+
+// return null on failure; if success, return the given project, or a new
+// one, if the given was null; create no new project if failure
+static AudacityProject *DoImportMIDI(
+   AudacityProject *pProject, const wxString &fileName);
+
 void OnImportRaw();
 
 void OnEditMetadata();

src/Project.cpp

@@ -2891,14 +2891,13 @@ void AudacityProject::OpenFiles(AudacityProject *proj)
       // there are no tracks, but there's an Undo history, etc, then
       // bad things can happen, including data files moving to the NEW
       // project directory, etc.
-      if (!proj || proj->mDirty || !proj->mTracks->IsEmpty()) {
-         // Open in a NEW window
-         proj = CreateNewAudacityProject();
-      }
+      if ( proj && ( proj->mDirty || !proj->mTracks->IsEmpty() ) )
+         proj = nullptr;
+
       // This project is clean; it's never been touched.  Therefore
       // all relevant member variables are in their initial state,
       // and it's okay to open a NEW project inside this window.
-      proj->OpenFile(fileName);
+      proj = AudacityProject::OpenProject( proj, fileName );
    }
 }
 
@@ -2927,6 +2926,18 @@ bool AudacityProject::WarnOfLegacyFile( )
 }
 
 
+AudacityProject *AudacityProject::OpenProject(
+   AudacityProject *pProject, const wxString &fileNameArg, bool addtohistory)
+{
+   AudacityProject *pNewProject = nullptr;
+   if ( ! pProject )
+      pProject = pNewProject = CreateNewAudacityProject();
+   auto cleanup = finally( [&] { if( pNewProject ) pNewProject->Close(true); } );
+   pProject->OpenFile( fileNameArg, addtohistory );
+   pNewProject = nullptr;
+   return pProject;
+}
+
 // FIXME:? TRAP_ERR This should return a result that is checked.
 //    See comment in AudacityApp::MRUOpen().
 void AudacityProject::OpenFile(const wxString &fileNameArg, bool addtohistory)

src/Project.h

@@ -242,6 +242,14 @@ class AUDACITY_DLL_API AudacityProject final : public wxFrame,
          const wxString &extrafilter = wxEmptyString);
    static bool IsAlreadyOpen(const wxString & projPathName);
    static void OpenFiles(AudacityProject *proj);
+
+   // Return the given project if that is not NULL, else create a project.
+   // Then open the given project path.
+   // But if an exception escapes this function, create no new project.
+   static AudacityProject *OpenProject(
+      AudacityProject *pProject,
+      const wxString &fileNameArg, bool addtohistory = true);
+
    void OpenFile(const wxString &fileName, bool addtohistory = true);
 
 private:

src/import/ImportLOF.cpp

@@ -307,9 +307,12 @@ void LOFImportFileHandle::lofOpenFiles(wxString* ln)
       doDurationAndScrollOffset();
 
       if (windowCalledOnce)
-      {
-         mProject = CreateNewAudacityProject();
-      }
+         // Cause a project to be created with the next import
+         mProject = nullptr;
+      else
+         // Apply any offset and duration directives of the first "window" line
+         // to the previously open project, not a new one.
+         ;
 
       windowCalledOnce = true;
 
@@ -388,7 +391,7 @@ void LOFImportFileHandle::lofOpenFiles(wxString* ln)
       if (targetfile.AfterLast(wxT('.')).IsSameAs(wxT("mid"), false)
           ||  targetfile.AfterLast(wxT('.')).IsSameAs(wxT("midi"), false))
       {
-         mProject->DoImportMIDI(targetfile);
+         mProject = AudacityProject::DoImportMIDI(mProject, targetfile);
       }
 
       // If not a midi, open audio file
@@ -399,9 +402,7 @@ void LOFImportFileHandle::lofOpenFiles(wxString* ln)
           * audio file. TODO: Some sort of message here? */
 
 #endif // USE_MIDI
-      {
-         mProject->OpenFile(targetfile);
-      }
+         mProject = AudacityProject::OpenProject( mProject, targetfile );
 
       // Set tok to right after filename
       temptok2.SetString(targettoken);
@@ -427,7 +428,11 @@ void LOFImportFileHandle::lofOpenFiles(wxString* ln)
             double offset;
 
             // handle an "offset" specifier
-            if (Internat::CompatibleToDouble(tokenholder, &offset))
+            if (!mProject)
+               // there was an import error,
+               // presumably with its own error message
+               ;
+            else if (Internat::CompatibleToDouble(tokenholder, &offset))
             {
                Track *t;
                TrackListIterator iter(mProject->GetTracks());
@@ -489,6 +494,9 @@ void LOFImportFileHandle::lofOpenFiles(wxString* ln)
 
 void LOFImportFileHandle::doDurationAndScrollOffset()
 {
+   if (!mProject)
+      return;
+
    bool doSomething = callDurationFactor || callScrollOffset;
    if (callDurationFactor)
    {