GaudiExcpetion instead of crash when outside of a DVAlgorithm

Phys/LoKiPhys/src/AuxDesktopBase.cpp

@@ -34,11 +34,21 @@ bool LoKi::AuxDesktopBase::allow_late_desktop_acquire( const bool allow ) {
 }
 
 // constructor from the desktop
-LoKi::AuxDesktopBase::AuxDesktopBase( const IDVAlgorithm* desktop ) : LoKi::AuxFunBase(), m_desktop( desktop ) {}
+LoKi::AuxDesktopBase::AuxDesktopBase( const IDVAlgorithm* desktop ) : LoKi::AuxFunBase(), m_desktop( desktop ) {
+  if ( !desktop )
+    throw GaudiException( "\n### No IDVAlgorithm.\n### You cannot use this function from outside of a "
+                          "DVAlgorithm.\n### Are you in FunTuple or an Hlt selection?",
+                          "LoKi::AuxDesktopBase::AuxDesktopBase", StatusCode::FAILURE );
+}
 
 // constructor from the desktop
 LoKi::AuxDesktopBase::AuxDesktopBase( const LoKi::Interface<IDVAlgorithm>& desktop )
-    : LoKi::AuxFunBase(), m_desktop( desktop ) {}
+    : LoKi::AuxFunBase(), m_desktop( desktop ) {
+  if ( !desktop )
+    throw GaudiException( "\n### No IDVAlgorithm.\n### You cannot use this function from outside of a "
+                          "DVAlgorithm.\n### Are you in FunTuple or an Hlt selection?",
+                          "LoKi::AuxDesktopBase::AuxDesktopBase", StatusCode::FAILURE );
+}
 
 // copy constructor
 LoKi::AuxDesktopBase::AuxDesktopBase( const LoKi::AuxDesktopBase& right )