Move the scheduling of end of the event loop to later in the loop

k4FWCore/components/IOSvc.cpp

@@ -57,6 +57,7 @@ StatusCode IOSvc::initialize() {
       return StatusCode::FAILURE;
     }
     m_entries = m_reader->getEvents();
+    debug() << "The input files have " << m_entries << " event entries available" << endmsg;
   }
 
   if ((m_entries && m_firstEventEntry >= m_entries) || m_firstEventEntry < 0) {
@@ -123,15 +124,6 @@ std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>, podio:
     }
   }
 
-  if (m_nextEntry >= m_entries) {
-    auto ep = serviceLocator()->as<IEventProcessor>();
-    StatusCode sc = ep->stopRun();
-    if (sc.isFailure()) {
-      error() << "Error when stopping run" << endmsg;
-      throw GaudiException("Error when stopping run", name(), StatusCode::FAILURE);
-    }
-  }
-
   std::vector<podio::CollectionBase*> collections;
 
   for (const auto& name : m_collectionNames) {
@@ -147,6 +139,16 @@ std::tuple<std::vector<podio::CollectionBase*>, std::vector<std::string>, podio:
 // should be removed so that they are deleted when the Frame is deleted
 // and not deleted when clearing the store
 void IOSvc::handle(const Incident& incident) {
+  if (m_reader.has_value() && incident.type() == "EndEvent" && m_nextEntry >= m_entries) {
+    debug() << "Reached the end of the input file. Scheduling a stop of the event loop" << endmsg;
+    auto ep = serviceLocator()->as<IEventProcessor>();
+    StatusCode sc = ep->stopRun();
+    if (sc.isFailure()) {
+      error() << "Error when stopping run" << endmsg;
+      throw GaudiException("Error when stopping run", name(), StatusCode::FAILURE);
+    }
+  }
+
   StatusCode code;
   if (m_hiveWhiteBoard) {
     if (!incident.context().valid()) {

test/k4FWCoreTest/CMakeLists.txt

@@ -19,6 +19,7 @@ limitations under the License.
 
 set(k4fwcoretest_plugin_sources
   src/components/ExampleEventHeaderConsumer.cpp
+  src/components/ExampleFailingConsumer.cpp
   src/components/ExampleFunctionalConsumer.cpp
   src/components/ExampleFunctionalConsumerKeyValues.cpp
   src/components/ExampleFunctionalConsumerMultiple.cpp
@@ -183,6 +184,13 @@ add_test_fwcore(FunctionalMultipleMemory options/ExampleFunctionalMultipleMemory
 add_test_fwcore(FunctionalMultipleMemoryEventContext options/ExampleFunctionalMultipleMemory.py --use-event-context)
 add_test_fwcore(FunctionalProducer options/ExampleFunctionalProducer.py PROPERTIES FIXTURES_SETUP ProducerFile)
 add_test_fwcore(FunctionalProducerAnother options/ExampleFunctionalProducer.py --second PROPERTIES FIXTURES_SETUP AnotherProducerFile)
+add_test_fwcore(FunctionalProducerSingleEvent options/ExampleFunctionalProducer.py --num-events=1 --IOSvc.Output=functional_producer_single_event.root PROPERTIES FIXTURES_SETUP ProducerFileSingleEvent)
+
+add_test_fwcore(ExampleFailingSingleEvent options/ExampleFailingSingleEvent.py
+   PROPERTIES
+     FIXTURES_REQUIRED ProducerFileSingleEvent
+     WILL_FAIL TRUE
+   )
 
 # PODIO_DEFAULT_WRITE_RNTUPLE needs to be unset because the test FunctionalMix reads through
 # PodioInput, which does not support RNTuple output

test/k4FWCoreTest/options/ExampleFailingSingleEvent.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2014-2024 Key4hep-Project.
+#
+# This file is part of Key4hep.
+# See https://key4hep.github.io/key4hep-doc/ for further info.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# This is an example using a producer with a single output and saving that to a file
+
+from k4FWCore import ApplicationMgr, IOSvc
+from Configurables import ExampleFailingConsumer, EventDataSvc
+
+iosvc = IOSvc("IOSvc")
+iosvc.Input = "functional_producer_single_event.root"
+
+failing_alg = ExampleFailingConsumer(InputCollection="MCParticles")
+
+ApplicationMgr(
+    TopAlg=[failing_alg],
+    ExtSvc=[EventDataSvc()],
+    EvtMax=-1,  # This is the important part here
+    EvtSel="NONE",
+)

test/k4FWCoreTest/src/components/ExampleFailingConsumer.cpp

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2014-2024 Key4hep-Project.
+ *
+ * This file is part of Key4hep.
+ * See https://key4hep.github.io/key4hep-doc/ for further info.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "edm4hep/MCParticleCollection.h"
+
+#include "k4FWCore/Consumer.h"
+
+#include <stdexcept>
+#include <string>
+
+/// This is an example algorithm that will throw an exception in its operator
+/// call. It still has an input to make it properly schedule
+struct ExampleFailingConsumer final : k4FWCore::Consumer<void(const edm4hep::MCParticleCollection&)> {
+
+  ExampleFailingConsumer(const std::string& name, ISvcLocator* svcLoc)
+      : Consumer(name, svcLoc, KeyValue("InputCollection", "MCParticles")) {}
+
+  void operator()(const edm4hep::MCParticleCollection&) const override {
+    throw std::runtime_error("An inevitable error. Really nothing we can do here");
+  }
+
+private:
+};
+
+DECLARE_COMPONENT(ExampleFailingConsumer);