From fbe7b7d35b8d26ef1c8647face08a6b188e8a5c2 Mon Sep 17 00:00:00 2001
From: Tim Fowler <Tim.Fowler@autodesk.com>
Date: Wed, 15 Apr 2020 13:17:31 -0400
Subject: [PATCH 1/2] MAYA-101454 Clear stage cach on file new/open.

---
 lib/mayaUsd/listeners/notice.cpp | 13 +++++++++++++
 plugin/adsk/plugin/plugin.cpp    |  5 +++++
 2 files changed, 18 insertions(+)

diff --git a/lib/mayaUsd/listeners/notice.cpp b/lib/mayaUsd/listeners/notice.cpp
index bb011074e2..a6016b7e2f 100644
--- a/lib/mayaUsd/listeners/notice.cpp
+++ b/lib/mayaUsd/listeners/notice.cpp
@@ -24,6 +24,11 @@ PXR_NAMESPACE_OPEN_SCOPE
 
 namespace {
 
+// Siple ref count for how many plugins have initialized the callback.
+// Used to keep the listener around until the last plugin asks for it
+// to be removed.
+static int _newOrOpenRegistrationCount = 0;
+
 static
 void
 _OnMayaNewOrOpenSceneCallback(void* /*clientData*/)
@@ -53,6 +58,10 @@ UsdMayaSceneResetNotice::UsdMayaSceneResetNotice()
 void
 UsdMayaSceneResetNotice::InstallListener()
 {
+    if (_newOrOpenRegistrationCount++ > 0) {
+        return;
+    }
+
     // Send scene reset notices when changing scenes (either by switching
     // to a new empty scene or by opening a different scene). We do not listen
     // for kSceneUpdate messages since those are also emitted after a SaveAs
@@ -79,6 +88,10 @@ UsdMayaSceneResetNotice::InstallListener()
 void
 UsdMayaSceneResetNotice::RemoveListener()
 {
+    if (_newOrOpenRegistrationCount-- > 1) {
+        return;
+    }
+    
     if (_afterNewCallbackId != 0) {
         MMessage::removeCallback(_afterNewCallbackId);
     }
diff --git a/plugin/adsk/plugin/plugin.cpp b/plugin/adsk/plugin/plugin.cpp
index 13007dd27b..c65adf2460 100644
--- a/plugin/adsk/plugin/plugin.cpp
+++ b/plugin/adsk/plugin/plugin.cpp
@@ -23,6 +23,7 @@
 #include <pxr/base/plug/plugin.h>
 #include <pxr/base/plug/registry.h>
 
+#include <mayaUsd/listeners/notice.h>
 #include <mayaUsd/base/api.h>
 #include <mayaUsd/nodes/proxyShapeBase.h>
 #include <mayaUsd/nodes/proxyShapePlugin.h>
@@ -134,6 +135,8 @@ MStatus initializePlugin(MObject obj)
         }
     }
 
+    UsdMayaSceneResetNotice::InstallListener();
+
     return status;
 }
 
@@ -180,5 +183,7 @@ MStatus uninitializePlugin(MObject obj)
     CHECK_MSTATUS(status);
 #endif
 
+    UsdMayaSceneResetNotice::RemoveListener();
+    
     return status;
 }

From 2e785ee2c1fb4a1a1dabbcc383dbf520d9400d15 Mon Sep 17 00:00:00 2001
From: Tim Fowler <Tim.Fowler@autodesk.com>
Date: Thu, 16 Apr 2020 20:08:56 -0400
Subject: [PATCH 2/2] typo fix

---
 lib/mayaUsd/listeners/notice.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/mayaUsd/listeners/notice.cpp b/lib/mayaUsd/listeners/notice.cpp
index a6016b7e2f..6f7d433113 100644
--- a/lib/mayaUsd/listeners/notice.cpp
+++ b/lib/mayaUsd/listeners/notice.cpp
@@ -24,7 +24,7 @@ PXR_NAMESPACE_OPEN_SCOPE
 
 namespace {
 
-// Siple ref count for how many plugins have initialized the callback.
+// Simple ref count for how many plugins have initialized the callback.
 // Used to keep the listener around until the last plugin asks for it
 // to be removed.
 static int _newOrOpenRegistrationCount = 0;