From 771d99559a46f5211885380528e363f32fbff839 Mon Sep 17 00:00:00 2001
From: tmadlener <thomas.madlener@desy.de>
Date: Tue, 11 Jun 2024 13:52:27 +0200
Subject: [PATCH] Make tests work by hiding forward declaration from CLING

---
 include/podio/GenericParameters.h | 11 +++++++----
 src/ROOTReader.cc                 |  2 ++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/podio/GenericParameters.h b/include/podio/GenericParameters.h
index 41df401a7..439af3d19 100644
--- a/include/podio/GenericParameters.h
+++ b/include/podio/GenericParameters.h
@@ -30,10 +30,10 @@ class RNTupleWriter;
 #endif
 
 namespace podio {
-class ROOTReader;
-}
 
-namespace podio {
+#if !defined(__CLING__)
+class ROOTReader;
+#endif
 
 /// The types which are supported in the GenericParameters
 using SupportedGenericDataTypes = std::tuple<int, float, std::string, double>;
@@ -133,12 +133,15 @@ class GenericParameters {
   friend void readGenericParameters(sio::read_device& device, GenericParameters& parameters, sio::version_type version);
 #endif
 
-  friend ROOTReader;
 #if PODIO_ENABLE_RNTUPLE
   friend RNTupleReader;
   friend RNTupleWriter;
 #endif
 
+#if !defined(__CLING__)
+  friend ROOTReader;
+#endif
+
   /// Get a reference to the internal map for a given type
   template <typename T>
   const MapType<detail::GetVectorType<T>>& getMap() const {
diff --git a/src/ROOTReader.cc b/src/ROOTReader.cc
index ecf0b29c1..3e786fb43 100644
--- a/src/ROOTReader.cc
+++ b/src/ROOTReader.cc
@@ -26,6 +26,8 @@ std::tuple<std::vector<root_utils::CollectionBranches>, std::vector<std::pair<st
 createCollectionBranchesIndexBased(TChain* chain, const podio::CollectionIDTable& idTable,
                                    const std::vector<root_utils::CollectionWriteInfoT>& collInfo);
 
+/// Helper struct to get the negative offsets from the end of the branches
+/// vector for the different types of generic parameters.
 template <typename T>
 struct TypeToBranchIndexOffset;