EMSUSD-266 Fixed bad USD/UFE notifications

lib/usdUfe/ufe/StagesSubject.cpp

@@ -452,11 +452,19 @@ void StagesSubject::stageChanged(
                         sendObjectAdd(sceneItem);
                         sentNotif = true;
                         break;
-                    } else if (
+                    }
+                    // Note : Do nothing here with didRemoveInertPrim and didRemoveNonInertPrim.
+                    // Indeed, we can get these if prim specs are removed from some layers, but it
+                    // does not mean that the prim is not longer in the composed stage. If the prim
+                    // was actually gone, we would either get an invalid prim (in which case we
+                    // would not even get here, and would send a object destroyed" notif in the else
+                    // bellow), or we would fall into the "HasInfoChange : Active" case bellow. If
+                    // nothing else sends a notif in the loop (typically via the info change :
+                    // active) we do not want to send the fallback notif, so act as if a notif was
+                    // sent.
+                    else if (
                         entry->flags.didRemoveInertPrim || entry->flags.didRemoveNonInertPrim) {
-                        sendObjectPostDelete(sceneItem);
                         sentNotif = true;
-                        break;
                     }
 
                     // Special case for "active" metadata.

lib/usdUfe/ufe/UsdUndoAddNewPrimCommand.cpp

@@ -148,7 +148,12 @@ UsdUndoAddNewPrimCommand::Ptr UsdUndoAddNewPrimCommand::create(
 Ufe::Selection getNewSelectionFromCommand(const UsdUndoAddNewPrimCommand& cmd)
 {
     Ufe::Selection newSelection;
-    newSelection.append(Ufe::Hierarchy::createItem(cmd.newUfePath()));
+    const auto     newItem = Ufe::Hierarchy::createItem(cmd.newUfePath());
+    // The add operation may have failed (for example, if attempting to edit instance proxies).
+    // Appending a null item throws an exception, which we dont want in this case.
+    if (newItem) {
+        newSelection.append(Ufe::Hierarchy::createItem(cmd.newUfePath()));
+    }
     return newSelection;
 }
 

test/lib/ufe/testDeleteCmd.py

@@ -394,10 +394,10 @@ def testDeleteRestrictionHierarchyWithChildrenInSessionLayer(self):
         stage.DefinePrim('/TreeBase/newChild', 'Xform')
         stage.SetEditTarget(stage.GetRootLayer())
 
-        # delete two USD prims and Maya's shape
+        # Delete the /TreeBase prim, at the usd root.
         ufeObs.reset()
         cmds.delete('|Tree_usd|Tree_usdShape,/TreeBase')
-        self.assertEqual(ufeObs.nbDeleteNotif() , 2)
+        self.assertEqual(ufeObs.nbDeleteNotif() , 1)
         self.assertFalse(stage.GetPrimAtPath('/TreeBase'))
         self.assertFalse(stage.GetPrimAtPath('/TreeBase/leavesXform/leaves'))
         self.assertFalse(stage.GetPrimAtPath('/TreeBase/trunk'))

test/lib/ufe/testObservableScene.py

@@ -19,9 +19,14 @@
 import fixturesUtils
 
 from maya import standalone
+from maya import cmds
+import mayaUtils
 
+from pxr import Usd
 import ufe
 
+from mayaUsd import lib as mayaUsdLib
+
 import os
 import sys
 import unittest
@@ -58,10 +63,15 @@ def notifications(self):
         return [self.add, self.delete, self.pathChange, self.subtreeInvalidate, self.composite]
 
 class UFEObservableSceneTest(unittest.TestCase):
-
+
+    pluginsLoaded = False
+
     @classmethod
     def setUpClass(cls):
         fixturesUtils.readOnlySetUpClass(__file__, loadPlugin=False)
+
+        if not cls.pluginsLoaded:
+            cls.pluginsLoaded = mayaUtils.isMayaUsdPluginLoaded()
 
     @classmethod
     def tearDownClass(cls):
@@ -120,6 +130,40 @@ def testObservableScene(self):
         #     ufe.Scene.notify(ufe.ObjectAdd(itemB))
         #     ufe.Scene.notify(ufe.ObjectAdd(itemC))
 
+    def testInertPrimAddRemoveNotifications(self):
+
+        cmds.file(new=True, force=True)
+
+        usdFilePath = cmds.internalVar(utd=1) + '/testInertPrimAddRemove.usda'
+        stage = Usd.Stage.CreateNew(usdFilePath)
+
+        fooPath = '/foo'
+        stage.DefinePrim(fooPath, 'Xform')
+
+        # Save out the file, and bring it back into Maya under a proxy shape.
+        stage.GetRootLayer().Save()
+        proxyShape = cmds.createNode('mayaUsdProxyShape')
+        cmds.setAttr('mayaUsdProxyShape1.filePath', usdFilePath, type='string')
+
+        stage = mayaUsdLib.GetPrim(proxyShape).GetStage()
+
+        # Work on the session layer, to easily clear changes.
+        sessionLayer = stage.GetSessionLayer()        
+        stage.SetEditTarget(sessionLayer)
+
+        snObs = TestObserver()
+        ufe.Scene.addObserver(snObs)
+
+        # Deactivate the prim...expect object delete notif.
+        fooPrim = stage.GetPrimAtPath(fooPath)
+        fooPrim.SetActive(False)
+        self.checkNotifications(snObs, [0,1,0,0,0,0])
+
+        # Clear session layer, expect an object added notif, as the inactive
+        # state was cleared from the session layer.
+        sessionLayer.Clear()
+        self.checkNotifications(snObs, [1,1,0,0,0,0])
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)