Shape Healing - initialize owires before ShapeAnalysis_FreeBounds's empty-input early return

src/ModelingAlgorithms/TKShHealing/GTests/ShapeAnalysis_FreeBounds_Test.cxx

@@ -0,0 +1,94 @@
+// Copyright (c) 2026 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#include <BRepBuilderAPI_MakeEdge.hxx>
+#include <BRepBuilderAPI_MakeFace.hxx>
+#include <BRepBuilderAPI_MakeWire.hxx>
+#include <BRep_Builder.hxx>
+#include <ShapeAnalysis_FreeBounds.hxx>
+#include <TopAbs_ShapeEnum.hxx>
+#include <TopExp_Explorer.hxx>
+#include <TopoDS_Compound.hxx>
+#include <TopoDS_Face.hxx>
+#include <TopoDS_Shape.hxx>
+#include <gp_Pnt.hxx>
+
+#include <gtest/gtest.h>
+
+namespace
+{
+static TopoDS_Face MakeSquareFace(const gp_Pnt& theA,
+                                  const gp_Pnt& theB,
+                                  const gp_Pnt& theC,
+                                  const gp_Pnt& theD)
+{
+  BRepBuilderAPI_MakeWire aMakeWire;
+  aMakeWire.Add(BRepBuilderAPI_MakeEdge(theA, theB).Edge());
+  aMakeWire.Add(BRepBuilderAPI_MakeEdge(theB, theC).Edge());
+  aMakeWire.Add(BRepBuilderAPI_MakeEdge(theC, theD).Edge());
+  aMakeWire.Add(BRepBuilderAPI_MakeEdge(theD, theA).Edge());
+  return BRepBuilderAPI_MakeFace(aMakeWire.Wire()).Face();
+}
+} // namespace
+
+// Baseline: a single closed face alone does not trigger the bug (see below).
+TEST(ShapeAnalysis_FreeBoundsTest, SingleFaceNoCrash)
+{
+  const TopoDS_Face aFace = MakeSquareFace(gp_Pnt(0.0, 0.0, 0.0),
+                                           gp_Pnt(1.0, 0.0, 0.0),
+                                           gp_Pnt(1.0, 1.0, 0.0),
+                                           gp_Pnt(0.0, 1.0, 0.0));
+
+  ShapeAnalysis_FreeBounds aFreeBounds(aFace, 0.01, true, true);
+  const TopoDS_Compound&   aClosed = aFreeBounds.GetClosedWires();
+  const TopoDS_Compound&   anOpen  = aFreeBounds.GetOpenWires();
+  (void)aClosed;
+  (void)anOpen;
+}
+
+// Regression: two disjoint closed faces used to crash SplitWires (see PR description).
+TEST(ShapeAnalysis_FreeBoundsTest, TwoDisjointFacesNoCrash)
+{
+  const TopoDS_Face aFaceA = MakeSquareFace(gp_Pnt(0.0, 0.0, 0.0),
+                                            gp_Pnt(1.0, 0.0, 0.0),
+                                            gp_Pnt(1.0, 1.0, 0.0),
+                                            gp_Pnt(0.0, 1.0, 0.0));
+  const TopoDS_Face aFaceB = MakeSquareFace(gp_Pnt(5.0, 5.0, 0.0),
+                                            gp_Pnt(6.0, 5.0, 0.0),
+                                            gp_Pnt(6.0, 6.0, 0.0),
+                                            gp_Pnt(5.0, 6.0, 0.0));
+
+  BRep_Builder    aBuilder;
+  TopoDS_Compound aCompound;
+  aBuilder.MakeCompound(aCompound);
+  aBuilder.Add(aCompound, aFaceA);
+  aBuilder.Add(aCompound, aFaceB);
+
+  ShapeAnalysis_FreeBounds aFreeBounds(aCompound, 0.01, true, true);
+  const TopoDS_Compound&   aClosed = aFreeBounds.GetClosedWires();
+  const TopoDS_Compound&   anOpen  = aFreeBounds.GetOpenWires();
+
+  int aNbClosed = 0;
+  for (TopExp_Explorer anExp(aClosed, TopAbs_WIRE); anExp.More(); anExp.Next())
+  {
+    ++aNbClosed;
+  }
+  int aNbOpen = 0;
+  for (TopExp_Explorer anExp(anOpen, TopAbs_WIRE); anExp.More(); anExp.Next())
+  {
+    ++aNbOpen;
+  }
+
+  EXPECT_EQ(aNbClosed, 2);
+  EXPECT_EQ(aNbOpen, 0);
+}

src/ModelingAlgorithms/TKShHealing/ShapeAnalysis/ShapeAnalysis_FreeBounds.cxx

@@ -207,6 +207,7 @@ static void connectWiresToWiresImpl(
 {
   if (iwires.IsNull() || !iwires->Length())
   {
+    owires = new NCollection_HSequence<TopoDS_Shape>; // was left null, later crashed Append
     return;
   }
   occ::handle<NCollection_HArray1<TopoDS_Shape>> arrwires =