PileupMT: Pass on overriden event info to output file

The event info changes made by EvtIdModifierSvc weren't being passed on to the output file, which made it impossible to run RAWtoALL on the produced RDOs.

This MR fixes that. It also reduces the number of high p_T minbias events loaded per hard scatter, to be a little more frugal.

Control/PileUpMT/src/PileUpMTAlg.cxx

@@ -58,17 +58,18 @@ PileUpMTAlg::PileUpMTAlg(const std::string& name, ISvcLocator* pSvcLocator)
 PileUpMTAlg::~PileUpMTAlg() {}
 
 StatusCode PileUpMTAlg::get_ei(StoreGateSvc& sg, std::unique_ptr<const xAOD::EventInfo>& ei_,
-                               bool /* pileup */) const {
+                               bool pileup) const {
+    std::string key = pileup ? "EventInfo" : "HSEventInfo";
     xAOD::EventInfo* newEi = new xAOD::EventInfo();
     xAOD::EventAuxInfo* eiAux = new xAOD::EventAuxInfo();
     newEi->setStore(eiAux);
-    SG::ReadHandle<xAOD::EventInfo> ei_h("EventInfo", sg.name());
+    SG::ReadHandle<xAOD::EventInfo> ei_h(key, sg.name());
     const xAOD::EventInfo* ei = ei_h.get();
     if (ei != nullptr) {
         *newEi = *ei;
     }
     else {
-        SG::ReadHandle<::EventInfo> ei2_h("EventInfo", sg.name());
+        SG::ReadHandle<::EventInfo> ei2_h(key, sg.name());
         const ::EventInfo* ei2 = ei2_h.get();
         if (ei2 == nullptr) {
             // Just in case
@@ -172,7 +173,7 @@ StatusCode PileUpMTAlg::initialize() {
             }
         }
     }
-    m_evtInfoContKey = fmt::format("{}Container", m_evtInfoKey.key());
+    m_evtInfoContKey = "PileUpEventInfo";
     ATH_CHECK(m_evtInfoKey.initialize());
     ATH_CHECK(m_evtInfoContKey.initialize());
     return StatusCode::SUCCESS;
@@ -192,6 +193,7 @@ StatusCode PileUpMTAlg::execute() {
     ATH_MSG_DEBUG("Executing " << name() << "...");
     // Gaudi::Hive::setCurrentContext(ctx);
     const EventContext& ctx = Gaudi::Hive::currentContext();
+    const auto& evtID = ctx.eventID();
     const long long hs_id = ctx.evt() + m_skippedHSEvents.value();
     ATH_CHECK(evtStore().retrieve());
     if (m_fracLowPt != 0) {
@@ -225,6 +227,13 @@ StatusCode PileUpMTAlg::execute() {
     overlaidEvt->setEvtStore(evtStore().get());
     overlaidEvt->clearSubEvents();
 
+    // This was the problem. Need to fix overlaidEvt using context run and lb number
+    overlaidEvt->setRunNumber(evtID.run_number());
+    overlaidEvt->setLumiBlock(evtID.lumi_block());
+    overlaidEvt->setEventNumber(evtID.event_number());
+    overlaidEvt->setBCID(evtID.bunch_crossing_id());
+    overlaidEvt->setTimeStamp(evtID.time_stamp());
+    overlaidEvt->setTimeStampNSOffset(evtID.time_stamp_ns_offset());
     // Pileup container
     SG::WriteHandle<xAOD::EventInfoContainer> puCont(m_evtInfoContKey, ctx);
     ATH_CHECK(puCont.record(std::make_unique<xAOD::EventInfoContainer>(),
@@ -239,7 +248,7 @@ StatusCode PileUpMTAlg::execute() {
 
     // Set properties
     bool sf_updated = false;
-    float lumi_sf = m_beamLumi->scaleFactor(hsEvt->runNumber(), hsEvt->lumiBlock(), sf_updated);
+    float lumi_sf = m_beamLumi->scaleFactor(evtID.run_number(), evtID.lumi_block(), sf_updated);
     float cur_avg_mu = lumi_sf * m_avgMu;
     overlaidEvt->setAverageInteractionsPerCrossing(cur_avg_mu);
     overlaidEvt->setActualInteractionsPerCrossing(m_beamInt->normFactor(0) * cur_avg_mu);