From 3a630d6e7cc711d5c322271735e711fa5197892c Mon Sep 17 00:00:00 2001
From: azv <azv@opencascade.com>
Date: Tue, 28 Nov 2017 16:24:09 +0300
Subject: [PATCH] Correct setting folder sub-elements on document opening

---
 src/Model/Model_Objects.cpp      | 5 ++++-
 src/ModelAPI/ModelAPI_Folder.cpp | 3 ---
 src/PartSet/PartSet_Tools.h      | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Model/Model_Objects.cpp b/src/Model/Model_Objects.cpp
index 7324960c6..0f3b779f4 100644
--- a/src/Model/Model_Objects.cpp
+++ b/src/Model/Model_Objects.cpp
@@ -957,7 +957,10 @@ void Model_Objects::synchronizeBackRefsForObject(const std::set<AttributePtr>& t
   for(; aNewIter != theNewRefs.end(); aNewIter++) {
     if (aData->refsToMe().find(*aNewIter) == aData->refsToMe().end()) {
       FeaturePtr aRefFeat = std::dynamic_pointer_cast<ModelAPI_Feature>((*aNewIter)->owner());
-      aData->addBackReference(aRefFeat, (*aNewIter)->id());
+      if (aRefFeat)
+        aData->addBackReference(aRefFeat, (*aNewIter)->id());
+      else // add back reference to a folder
+        aData->addBackReference((*aNewIter)->owner(), (*aNewIter)->id());
     }
   }
   if (theNewRefs.size() != aData->refsToMe().size()) { // some back ref must be removed
diff --git a/src/ModelAPI/ModelAPI_Folder.cpp b/src/ModelAPI/ModelAPI_Folder.cpp
index 965529374..1cc97cb36 100644
--- a/src/ModelAPI/ModelAPI_Folder.cpp
+++ b/src/ModelAPI/ModelAPI_Folder.cpp
@@ -38,9 +38,6 @@ void ModelAPI_Folder::initAttributes()
 {
   data()->addAttribute(FIRST_FEATURE_ID(), ModelAPI_AttributeReference::typeId());
   data()->addAttribute(LAST_FEATURE_ID(),  ModelAPI_AttributeReference::typeId());
-  // nullify references for sure
-  reference(FIRST_FEATURE_ID())->setValue(ObjectPtr());
-  reference(LAST_FEATURE_ID())->setValue(ObjectPtr());
 }
 
 void ModelAPI_Folder::execute()
diff --git a/src/PartSet/PartSet_Tools.h b/src/PartSet/PartSet_Tools.h
index 486d361e0..1a8beb670 100755
--- a/src/PartSet/PartSet_Tools.h
+++ b/src/PartSet/PartSet_Tools.h
@@ -256,7 +256,7 @@ public:
     std::set<AttributePtr>::const_iterator anIt;
     for (anIt = aRefsList.cbegin(); anIt != aRefsList.cend(); ++anIt) {
       FeaturePtr aRefFeature = std::dynamic_pointer_cast<ModelAPI_Feature>((*anIt)->owner());
-      if (aRefFeature->getKind() == theFeatureId)
+      if (aRefFeature && aRefFeature->getKind() == theFeatureId)
         return aRefFeature;
     }
     return FeaturePtr();
-- 
2.39.2