Merge branch 'EmptyCFNodeError' into 'master'

Error message for empty CF node

See merge request atlas/athena!35485

Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Menu/CFValidation.py

@@ -20,6 +20,11 @@ def findViewAlgs( inputNodes, viewNodes ):
         # If node is a sequence, explore further
         if isSequence( node ):
 
+            # Empty nodes can cause Gaudi scheduler bug https://gitlab.cern.ch/gaudi/Gaudi/-/issues/135
+            if len( node.getChildren() ) == 0 and node.ModeOR:
+
+              raise RuntimeError( "Empty CF sequence in OR mode can cause Gaudi scheduler bug. Please remove " + node.getName() )
+
             # Identify view CF nodes
             if node.getName() in viewNodes.keys():
 

Trigger/TriggerCommon/TriggerMenuMT/python/HLTMenuConfig/Test/ViewCFTest.py

@@ -20,8 +20,12 @@ class ViewCFTest( unittest.TestCase ):
         vdv1 = CfgMgr.AthViews__ViewDataVerifier("vdv1")
         vdv2 = CfgMgr.AthViews__ViewDataVerifier("vdv2")
 
-        # Add an algorithm to a sequence
+        # Test error for empty sequence
         topSequence += seqOR( "makeViewSequence" )
+        with self.assertRaisesRegex( RuntimeError, "Please remove makeViewSequence" ):
+            findViewAlgs( topSequence.getChildren(), {} )
+
+        # Add an algorithm to the sequence
         topSequence.makeViewSequence += evca1
         #topSequence.makeViewSequence += evca2