Merge branch 'RunDependentSimPatch_ATLASSIM-3399_21.0' into '21.0'

Veto lumiblocks with zero events from being used by RunDMC code

See merge request !4007

Former-commit-id: 962f5b69ad4359cd03adc9d11fe9852638d5b3d4

Simulation/Digitization/python/DigitizationFlags.py

@@ -470,11 +470,18 @@ class RunAndLumiOverrideList(JobProperty):
     def __setattr__(self, name, n_value):
         KeysRequired=('run','lb','starttstamp','evts','mu','force_new')
         if name=='StoredValue' and not(self._locked):
+            def noEventsInLumiBlock(element):
+                return element['evts'] == 0
+
             for element in n_value:
                 if not type(element) == dict :
                     raise ValueError( ' %s is not the expected type (dict) for an element of RunAndLumiOverrideList' % (element.__str__()) )
                 if not set(element) >= set(KeysRequired):
                     raise ValueError( 'Not all required keys for RunAndLumiOverrideList (%s) were found in %s' % (KeysRequired.__repr__(), element.__repr__()) )
+                if noEventsInLumiBlock(element):
+                    logDigitizationFlags.warning('Found lumiblock with no events!  This lumiblock will not be used:\n (%s)' % (element.__str__()) )
+            from itertools import ifilterfalse
+            n_value[:] = ifilterfalse(noEventsInLumiBlock, n_value)
         JobProperty.__setattr__(self, name, n_value)
     def getEvtsMax(self): #todo -- check if locked first?
         """Get the total number of events requested by this fragment of the task"""