From e74b940a5dc8a192668d98609cc7710569f85f27 Mon Sep 17 00:00:00 2001
From: Pierre Baillargeon <Pierre.Baillargeon@autodesk.com>
Date: Thu, 30 Nov 2023 08:51:46 -0500
Subject: [PATCH] EMSUSD-647 fix copying the proxy shape node

When Maya copies a Maya node, it actually export the selected nodes into a temporary file. When the node is a MayaUSD node, this export automatically prompt the user to save the dirty USD files. To avoid this, we now detect that we are exporting due to a copy operation and force saving the USD layer into the Maya scene file.
---
 lib/mayaUsd/nodes/layerManager.cpp | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/lib/mayaUsd/nodes/layerManager.cpp b/lib/mayaUsd/nodes/layerManager.cpp
index ae524852a8..1e76a5feee 100644
--- a/lib/mayaUsd/nodes/layerManager.cpp
+++ b/lib/mayaUsd/nodes/layerManager.cpp
@@ -26,6 +26,7 @@
 #include <mayaUsd/utils/utilFileSystem.h>
 #include <mayaUsd/utils/utilSerialization.h>
 
+#include <pxr/base/arch/env.h>
 #include <pxr/base/tf/instantiateType.h>
 #include <pxr/base/tf/weakBase.h>
 #include <pxr/usd/ar/resolver.h>
@@ -194,6 +195,14 @@ bool isCrashing()
 #endif
 }
 
+bool isCopyingSceneNodes()
+{
+    // When Maya is copy nodes, it exports them and sets this environment
+    // variable during the export to let exporters know it is cutting or
+    // copying nodes in a temporary Maya scene file.
+    return PXR_NS::ArchHasEnv("MAYA_CUT_COPY_EXPORT");
+}
+
 constexpr auto kSaveOptionUICmd = "usdFileSaveOptions(true);";
 
 } // namespace
@@ -412,9 +421,11 @@ void LayerDatabase::prepareForWriteCheck(bool* retCode, bool isExport)
 
         int dialogResult = true;
 
-        if (MGlobal::kInteractive == MGlobal::mayaState() && !isCrashing()
-            && LayerDatabase::instance().saveInteractionRequired()) {
-            MGlobal::executeCommand(kSaveOptionUICmd, dialogResult);
+        if (!isCopyingSceneNodes()) {
+            if (MGlobal::kInteractive == MGlobal::mayaState() && !isCrashing()
+                && LayerDatabase::instance().saveInteractionRequired()) {
+                MGlobal::executeCommand(kSaveOptionUICmd, dialogResult);
+            }
         }
 
         if (dialogResult) {
@@ -619,10 +630,10 @@ bool LayerDatabase::saveUsd(bool isExport)
     auto opt = MayaUsd::utils::serializeUsdEditsLocationOption();
 
     if (MayaUsd::utils::kIgnoreUSDEdits != opt) {
-        // When Maya is crashing, we don't want to save the the USD file to avoid
-        // overwriting them with possibly unwanted data. Instead, we will save the
-        // USD data inside the temporary crash recovery Maya file.
-        if (isCrashing()) {
+        // When Maya is crashing or copying/cutting scene nodes, we don't want to
+        // save the the USD file to avoid overwriting them with possibly unwanted
+        // data. Instead, we will save the USD data inside the temporary crash recovery Maya file.
+        if (isCrashing() || isCopyingSceneNodes()) {
             result = kPartiallyCompleted;
             opt = MayaUsd::utils::kSaveToMayaSceneFile;
         } else if (_batchSaveDelegate && _proxiesToSave.size() > 0) {