MuonTrackSteeringTools: Another attempt to fix dangling Surface references.

finalize() is still to late to clean up the garbage in MuPatCandidateTool,
as we also clean stores in step.  Try moving deleting the garbage
to stop().

See ATLASRECTS-5843.

MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MuPatCandidateTool.cxx

@@ -58,9 +58,13 @@ namespace Muon {
   }
 
   StatusCode MuPatCandidateTool::finalize() {
+    return StatusCode::SUCCESS;
+  }
+
+  StatusCode MuPatCandidateTool::stop() {
 
     // Clean up all garbage now.
-    // If we leave it for the dtor, we may end up with dangling references
+    // If we leave it for later, we may end up with dangling references
     // to Surface objects that have already been deleted.
     for (CacheEntry& ent : m_cache) {
       ent.cleanUp();

MuonSpectrometer/MuonReconstruction/MuonTrackMakers/MuonTrackMakerTools/MuonTrackSteeringTools/src/MuPatCandidateTool.h

@@ -65,13 +65,16 @@ namespace Muon {
     MuPatCandidateTool(const std::string&, const std::string&, const IInterface*);
     
     /** destructor */
-    ~MuPatCandidateTool() = default;
+    virtual ~MuPatCandidateTool() = default;
     
     /** initialize method, method taken from bass-class AlgTool */
-    StatusCode initialize();
+    virtual StatusCode initialize() override;
 
     /** finialize method, method taken from bass-class AlgTool */
-    StatusCode finalize();
+    virtual StatusCode finalize() override;
+
+    /** stop method, used to clean up garbage */
+    virtual StatusCode stop() override;
     
     /** @brief access to tool interface */
     static const InterfaceID& interfaceID() { return IID_MuPatCandidateTool; }