Fix for loading RealDataItem with linked instrument

Redmine: #2108

GUI/coregui/Models/RealDataItem.cpp

@@ -28,13 +28,10 @@ const QString RealDataItem::T_INTENSITY_DATA = "Intensity data";
 
 RealDataItem::RealDataItem()
     : SessionItem(Constants::RealDataType)
-    , m_linkedInstrument(0)
+    , m_linkedInstrument(nullptr)
 {
     setItemName(QStringLiteral("undefined"));
 
-    addProperty(P_INSTRUMENT_ID, QString());
-    addProperty(P_INSTRUMENT_NAME, QString());
-
     // Registering this tag even without actual data item to avoid troubles in copying RealDataItem
     registerTag(T_INTENSITY_DATA, 1, 1,
                 QStringList() << Constants::IntensityDataType << Constants::SpecularDataType);
@@ -43,6 +40,9 @@ RealDataItem::RealDataItem()
     // what happens if default tag is not present.
     setDefaultTag(T_INTENSITY_DATA);
 
+    addProperty(P_INSTRUMENT_ID, QString());
+    addProperty(P_INSTRUMENT_NAME, QString());
+
     mapper()->setOnPropertyChange([this](const QString& name) {
         if (name == P_NAME && getItem(T_INTENSITY_DATA))
             updateIntensityDataFileName();
@@ -151,8 +151,5 @@ void RealDataItem::updateIntensityDataFileName()
 void RealDataItem::updateToInstrument()
 {
     DataItem* item = dataItem();
-    assert(item->getOutputData()
-           && "RealDataItem::updateToInstrument assertion failed: underlying data item doesn't "
-              "contain data");
     JobItemUtils::setIntensityItemAxesUnits(item, m_linkedInstrument);
 }