0003279: Error 'invalid DAG' after deleting sketch using expressions

src/App/Document.cpp

@@ -2867,6 +2867,9 @@ void Document::_removeObject(DocumentObject* pcObject)
 void Document::breakDependency(DocumentObject* pcObject, bool clear)
 {
     // Nullify all dependent objects
+    std::vector<DocumentObject *> docObjs;
+    pcObject->ExpressionEngine.getDocumentObjectDeps(docObjs);
+
     for (std::map<std::string,DocumentObject*>::iterator it = d->objectMap.begin(); it != d->objectMap.end(); ++it) {
         std::map<std::string,App::Property*> Map;
         it->second->getPropertyMap(Map);
@@ -2929,6 +2932,14 @@ void Document::breakDependency(DocumentObject* pcObject, bool clear)
                 }
             }
         }
+
+        if (std::find(docObjs.begin(), docObjs.end(), it->second) != docObjs.end()) {
+            std::vector<App::ObjectIdentifier> paths;
+            pcObject->ExpressionEngine.getPathsToDocumentObject(it->second, paths);
+            for (std::vector<App::ObjectIdentifier>::iterator jt = paths.begin(); jt != paths.end(); ++jt) {
+                pcObject->ExpressionEngine.setValue(*jt, nullptr);
+            }
+        }
     }
 }
 

src/App/PropertyExpressionEngine.cpp

@@ -680,6 +680,44 @@ void PropertyExpressionEngine::getDocumentObjectDeps(std::vector<DocumentObject
     }
 }
 
+/**
+ * @brief Find paths to document object.
+ * @param obj Document object
+ * @param paths Object identifier
+ */
+
+void PropertyExpressionEngine::getPathsToDocumentObject(DocumentObject* obj,
+                                 std::vector<App::ObjectIdentifier> & paths) const
+{
+    DocumentObject * owner = freecad_dynamic_cast<DocumentObject>(getContainer());
+
+    if (owner == 0)
+        return;
+
+    ExpressionMap::const_iterator i = expressions.begin();
+
+    while (i != expressions.end()) {
+        std::set<ObjectIdentifier> deps;
+
+        i->second.expression->getDeps(deps);
+
+        std::set<ObjectIdentifier>::const_iterator j = deps.begin();
+
+        while (j != deps.end()) {
+            const ObjectIdentifier & p = *j;
+            DocumentObject* docObj = p.getDocumentObject();
+
+            if (docObj == obj && docObj != owner) {
+                paths.push_back(i->first);
+                break;
+            }
+
+            ++j;
+        }
+        ++i;
+    }
+}
+
 /**
  * @brief Determine whether any dependencies of any of the registered expressions have been touched.
  * @return True if at least on dependency has been touched.

src/App/PropertyExpressionEngine.h

@@ -101,6 +101,8 @@ public:
 
     void getDocumentObjectDeps(std::vector<DocumentObject*> & docObjs) const;
 
+    void getPathsToDocumentObject(DocumentObject*, std::vector<App::ObjectIdentifier> & paths) const;
+
     bool depsAreTouched() const;
 
     boost::unordered_map<const App::ObjectIdentifier, const ExpressionInfo> getExpressions() const;