From 012c4558e40f9d06c0918c6d875ce189416ce24f Mon Sep 17 00:00:00 2001
From: tmadlener <thomas.madlener@desy.de>
Date: Fri, 17 Nov 2023 10:12:26 +0100
Subject: [PATCH] Default to reading all collections and allow to limit them

---
 k4FWCore/components/PodioInput.cpp | 9 ++++++++-
 k4FWCore/components/PodioInput.h   | 3 ++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/k4FWCore/components/PodioInput.cpp b/k4FWCore/components/PodioInput.cpp
index 949a9053..28d655d7 100644
--- a/k4FWCore/components/PodioInput.cpp
+++ b/k4FWCore/components/PodioInput.cpp
@@ -193,7 +193,14 @@ void PodioInput::operator()() const {
     info() << "No EventHeader collection found in the event. Not reading it" << endmsg;
   }
 
-  for (const auto& collName : m_collectionNames) {
+  const auto& collsToRead = [&]() {
+    if (m_collectionNames.empty()) {
+      return m_podioDataSvc->getEventFrame().getAvailableCollections();
+    } else {
+      return m_collectionNames.value();
+    }}();
+
+  for (const auto& collName : collsToRead) {
     debug() << "Registering collection to read " << collName << endmsg;
     if (!m_podioDataSvc->hasCollection(collName)) {
       warning() << "Collection " << collName << " is not available from file." << endmsg;
diff --git a/k4FWCore/components/PodioInput.h b/k4FWCore/components/PodioInput.h
index 3a41afc6..978d821e 100644
--- a/k4FWCore/components/PodioInput.h
+++ b/k4FWCore/components/PodioInput.h
@@ -46,7 +46,8 @@ class PodioInput final : public Gaudi::Functional::Consumer<void(), BaseClass_t>
   template <typename T> void maybeRead(std::string_view collName) const;
   void                       fillReaders();
   // Name of collections to read. Set by option collections (this is temporary)
-  Gaudi::Property<std::vector<std::string>> m_collectionNames{this, "collections", {}, "Places of collections to read"};
+  Gaudi::Property<std::vector<std::string>> m_collectionNames{
+      this, "collections", {}, "Collections that should be read (default all)"};
   // Data service: needed to register objects and get collection IDs. Just an observing pointer.
   PodioDataSvc*                                                             m_podioDataSvc;
   mutable std::map<std::string_view, std::function<void(std::string_view)>> m_readers;