npsim does not run correctly with steering files

[c-dilks]

Environment: (where does this bug occur, have you tried other environments)

• Which branch (often main for latest released): main
• Which version (or HEAD for the most recent on git): 1.1.0

Steps to reproduce: (give a step by step account of how to trigger the bug)

1. Compare the following two npsim calls:

(a) Using CLI options directly:

npsim \
  --runType        batch                                              \
  --compactFile    ${DETECTOR_PATH}/${DETECTOR_CONFIG}_drich_only.xml \
  --outputFile     sim.edm4hep.root                                   \
  --enableGun                                                         \
  --numberOfEvents 10                                                 \
  --gun.particle   "pi+"                                              \
  --gun.energy     "20.0*GeV"                                         \
  --gun.direction  "(0.399, 0.0, 0.917)"

(b) Using a steering file:

Steering file steer.py:

from DDSim.DD4hepSimulation import DD4hepSimulation
from g4units import GeV

SIM = DD4hepSimulation()
SIM.enableGun      = True
SIM.numberOfEvents = 10
SIM.gun.particle   = "pi+"
SIM.gun.energy     = 20.0*GeV
SIM.gun.direction  = (0.399, 0.0, 0.917)

with npsim call:

npsim \
  --runType        batch                                              \
  --compactFile    ${DETECTOR_PATH}/${DETECTOR_CONFIG}_drich_only.xml \
  --outputFile     sim.edm4hep.root                                   \
  --steeringFile   steer.py

2. Check the output, e.g.:

root -l sim.edm4hep.root -e 'events->Draw("DRICHHits.position.y:DRICHHits.position.x")'

Expected Result: (what do you expect when you execute the steps above)

Both 1(a) and 1(b) produce the same results, and plotting with step 2 returns:

Actual Result: (what do you get when you execute the steps above)

Running with 1(b) returns no DRICHHits and the plot is therefore empty. This is also happens when running with ddsim as opposed to npsim, since ddsim does not have the additional settings required for RICH detectors.

Additional Context

The diff of output from 1(a) to 1(b) has some clues (irrelevant differences removed):

50c50
< DDSim.Helper.Filter INFO ReqFilt {'edep0', 'opticalphotons'}
---
> DDSim.Helper.Filter INFO ReqFilt {'edep1kev', 'edep0'}

53d52
< DDSim            INFO        replace default action with : Geant4OpticalTrackerAction

56c55
< DDSim.Helper.Filter INFO Adding filter 'opticalphotons' matched with 'DRICH' to sensitive detector for 'DRICH' 
---
> DDSim.Helper.Filter INFO Adding default filter 'edep1kev' to sensitive detector for 'DRICH' 

65,66d63
< Geant4UI         INFO  +++ CerenkovPhys> Install Geant4 control directory:/ddg4/CerenkovPhys/
< Geant4UI         INFO  +++ OpticalGammaPhys> Install Geant4 control directory:/ddg4/OpticalGammaPhys/

105,107d101
< CerenkovPhys     INFO  +++ Constructing: maxNumPhotonsPerStep:10 maxBeta:10.000000 track secondaries:NO  stack photons:YES track secondaries:NO 
< OpticalGammaPhys INFO  +++ Constructing optical_photon processes:
< OpticalGammaPhys INFO  +++              G4OpAbsorption G4OpRayleigh G4OpMieHG G4OpBoundaryProcess