epoch to clear

Author: deboisj

lib/usdUfe/undo/UsdUndoStateDelegate.cpp

@@ -65,6 +65,10 @@ class SpecCopier : public SdfAbstractDataSpecVisitor
 
 namespace USDUFE_NS_DEF {
 
+uint32_t UsdUndoStateDelegate::_invertEpoch { 0 };
+
+void UsdUndoStateDelegate::beginInvert() { ++_invertEpoch; }
+
 UsdUndoStateDelegate::UsdUndoStateDelegate()
     : _dirty(false)
     , _setMessageAlreadyShowed(false)
@@ -106,6 +110,15 @@ void UsdUndoStateDelegate::invertSetField(
     TF_DEBUG(USDUFE_UNDOSTATEDELEGATE)
         .Msg("Inverting set Field '%s' for Spec '%s'\n", fieldName.GetText(), path.GetText());
 
+    // Clear the tracking set when a new undo/redo replay starts. beginReplay()
+    // increments _replayEpoch at the top of each doInvert() call. Without this,
+    // entries from a previous undo would persist into a subsequent redo and
+    // incorrectly filter children that invertDeleteSpec is about to recreate.
+    if (_invertEpoch != _lastSeenEpoch) {
+        _specsDeletedByInvertCreate.clear();
+        _lastSeenEpoch = _invertEpoch;
+    }
+
     // When restoring a PrimChildren or PropertyChildren field, the inverse value may
     // reference children whose specs no longer exist. There are two reasons this happens:
     //

lib/usdUfe/undo/UsdUndoStateDelegate.h

@@ -49,6 +49,10 @@ class USDUFE_PUBLIC UsdUndoStateDelegate : public SdfLayerStateDelegateBase
 
     static UsdUndoStateDelegateRefPtr New();
 
+    /// Called at the start of each undo/redo replay. Increments an epoch counter, useful
+    /// to manage any per-undo/redo state.
+    static void beginInvert();
+
 private:
     void invertSetField(const SdfPath& path, const TfToken& fieldName, const VtValue& inverse);
     void invertCreateSpec(const SdfPath& path, bool inert);
@@ -131,7 +135,11 @@ class USDUFE_PUBLIC UsdUndoStateDelegate : public SdfLayerStateDelegateBase
     bool           _setMessageAlreadyShowed;
 
     // Tracks specs deleted by invertCreateSpec during an undo/redo replay.
+    // See invertSetField and invertCreateSpec for detailed documentation.
     std::unordered_set<SdfPath, SdfPath::Hash> _specsDeletedByInvertCreate;
+
+    uint32_t _lastSeenEpoch { 0 };
+    static uint32_t _invertEpoch;
 };
 
 } // namespace USDUFE_NS_DEF

lib/usdUfe/undo/UsdUndoableItem.cpp

@@ -17,6 +17,7 @@
 #include "UsdUndoableItem.h"
 
 #include <usdUfe/undo/UsdUndoBlock.h>
+#include <usdUfe/undo/UsdUndoStateDelegate.h>
 
 #include <pxr/usd/sdf/changeBlock.h>
 
@@ -33,6 +34,9 @@ void UsdUndoableItem::doInvert()
                         "stack.");
     }
 
+    // Signal so that any per-invert tracking state can be updated.
+    UsdUndoStateDelegate::beginInvert();
+
     UsdUndoBlock undoBlock(this);
 
     // call invert functions in reverse order