From 40b763481cc7d738cc936614a1cb620cc0e0613d Mon Sep 17 00:00:00 2001
From: tmadlener <thomas.madlener@desy.de>
Date: Tue, 11 Jun 2024 11:24:30 +0200
Subject: [PATCH] Make older compilers happy with in place construction

---
 include/podio/utilities/RootHelpers.h | 10 ++++++++++
 src/ROOTLegacyReader.cc               |  2 +-
 src/ROOTReader.cc                     |  7 +++----
 src/ROOTWriter.cc                     |  2 +-
 4 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/include/podio/utilities/RootHelpers.h b/include/podio/utilities/RootHelpers.h
index bd8f9a57b..8e3118b4d 100644
--- a/include/podio/utilities/RootHelpers.h
+++ b/include/podio/utilities/RootHelpers.h
@@ -26,6 +26,16 @@ namespace root_utils {
   /// write a collection. Needed to cache the branch pointers and avoid having to
   /// get them from a TTree/TChain for every event.
   struct CollectionBranches {
+    CollectionBranches() = default;
+    ~CollectionBranches() = default;
+    CollectionBranches(const CollectionBranches&) = delete;
+    CollectionBranches& operator=(const CollectionBranches&) = delete;
+    CollectionBranches(CollectionBranches&&) = default;
+    CollectionBranches& operator=(CollectionBranches&&) = default;
+
+    CollectionBranches(TBranch* dataBranch) : data(dataBranch) {
+    }
+
     TBranch* data{nullptr};
     std::vector<TBranch*> refs{};
     std::vector<TBranch*> vecs{};
diff --git a/src/ROOTLegacyReader.cc b/src/ROOTLegacyReader.cc
index 83f160615..494ec4301 100644
--- a/src/ROOTLegacyReader.cc
+++ b/src/ROOTLegacyReader.cc
@@ -207,7 +207,7 @@ void ROOTLegacyReader::createCollectionBranches(const std::vector<root_utils::Co
 
     m_storedClasses.emplace_back(name, std::make_tuple(collType, isSubsetColl, collSchemaVersion, collectionIndex++));
 
-    m_collectionBranches.push_back(branches);
+    m_collectionBranches.emplace_back(std::move(branches));
   }
 }
 
diff --git a/src/ROOTReader.cc b/src/ROOTReader.cc
index d65753c22..ecf0b29c1 100644
--- a/src/ROOTReader.cc
+++ b/src/ROOTReader.cc
@@ -227,8 +227,7 @@ void ROOTReader::initCategory(CategoryInfo& catInfo, const std::string& category
   // Finally set up the branches for the parameters
   if (m_fileVersion < podio::version::Version{0, 99, 99}) {
     root_utils::CollectionBranches paramBranches{};
-    paramBranches.data = root_utils::getBranch(catInfo.chain.get(), root_utils::paramBranchName);
-    catInfo.branches.push_back(paramBranches);
+    catInfo.branches.emplace_back(root_utils::getBranch(catInfo.chain.get(), root_utils::paramBranchName));
   } else {
     catInfo.branches.emplace_back(root_utils::getBranch(catInfo.chain.get(), root_utils::intKeyName));
     catInfo.branches.emplace_back(root_utils::getBranch(catInfo.chain.get(), root_utils::intValueName));
@@ -373,7 +372,7 @@ createCollectionBranchesIndexBased(TChain* chain, const podio::CollectionIDTable
     collBranches.emplace_back(std::move(branches));
   }
 
-  return {collBranches, storedClasses};
+  return {std::move(collBranches), storedClasses};
 }
 
 std::tuple<std::vector<root_utils::CollectionBranches>, std::vector<std::pair<std::string, detail::CollectionInfo>>>
@@ -419,7 +418,7 @@ createCollectionBranches(TChain* chain, const podio::CollectionIDTable& idTable,
     collBranches.emplace_back(std::move(branches));
   }
 
-  return {collBranches, storedClasses};
+  return {std::move(collBranches), storedClasses};
 }
 
 } // namespace podio
diff --git a/src/ROOTWriter.cc b/src/ROOTWriter.cc
index a2056cc6b..df8e810fd 100644
--- a/src/ROOTWriter.cc
+++ b/src/ROOTWriter.cc
@@ -120,7 +120,7 @@ void ROOTWriter::initBranches(CategoryInfo& catInfo, const std::vector<root_util
       }
     }
 
-    catInfo.branches.push_back(branches);
+    catInfo.branches.emplace_back(std::move(branches));
     catInfo.collInfo.emplace_back(catInfo.idTable.collectionID(name).value(), std::string(coll->getTypeName()),
                                   coll->isSubsetCollection(), coll->getSchemaVersion());
   }