From 55f888621804f6b826c78756c72d1b7a33146a45 Mon Sep 17 00:00:00 2001
From: Jan Fiete <jgrosseo@cern.ch>
Date: Wed, 23 Jun 2021 11:17:13 +0200
Subject: [PATCH 1/2] adding meta data to aod merger

---
 Analysis/Core/src/AODMerger.cxx | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Analysis/Core/src/AODMerger.cxx b/Analysis/Core/src/AODMerger.cxx
index 13d71784753d2..36e0a0ed2f81f 100644
--- a/Analysis/Core/src/AODMerger.cxx
+++ b/Analysis/Core/src/AODMerger.cxx
@@ -73,6 +73,7 @@ int main(int argc, char* argv[])
   in.open(inputCollection);
   TString line;
   bool connectedToAliEn = false;
+  TMap* metaData = nullptr;
   int mergedDFs = 0;
   while (in.good()) {
     in >> line;
@@ -94,6 +95,30 @@ int main(int argc, char* argv[])
     keyList->Sort();
 
     for (auto key1 : *keyList) {
+      if (((TObjString*)key1)->GetString().EqualTo("metaData")) {
+        auto metaDataCurrentFile = (TMap*)inputFile->Get("metaData");
+        if (metaData == nullptr) {
+          metaData = metaDataCurrentFile;
+          // outputFile->WriteObject(&metaData, "metaData");
+          outputFile->cd();
+          metaData->Write("metaData", TObject::kSingleKey);
+        } else {
+          for (auto metaDataPair : *metaData) {
+            auto metaDataKey = ((TPair*)metaDataPair)->Key();
+            if (metaDataCurrentFile->Contains(((TObjString*)metaDataKey)->GetString())) {
+              auto value = (TObjString*)metaData->GetValue(((TObjString*)metaDataKey)->GetString());
+              auto valueCurrentFile = (TObjString*)metaDataCurrentFile->GetValue(((TObjString*)metaDataKey)->GetString());
+              if (!value->GetString().EqualTo(valueCurrentFile->GetString())) {
+                printf("WARNING: Metadata differs between input files. Key %s : %s vs. %s\n", ((TObjString*)metaDataKey)->GetString().Data(),
+                       value->GetString().Data(), valueCurrentFile->GetString().Data());
+              }
+            } else {
+              printf("WARNING: Metadata differs between input files. Key %s is not present in current file\n", ((TObjString*)metaDataKey)->GetString().Data());
+            }
+          }
+        }
+      }
+
       if (!((TObjString*)key1)->GetString().BeginsWith("DF_")) {
         continue;
       }

From fea22f1594129c366431fdb1998542c921e66096 Mon Sep 17 00:00:00 2001
From: jgrosseo <jgrosseo@cern.ch>
Date: Thu, 24 Jun 2021 09:24:02 +0200
Subject: [PATCH 2/2] Update AODMerger.cxx

---
 Analysis/Core/src/AODMerger.cxx | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Analysis/Core/src/AODMerger.cxx b/Analysis/Core/src/AODMerger.cxx
index 36e0a0ed2f81f..c26b0119e9cb7 100644
--- a/Analysis/Core/src/AODMerger.cxx
+++ b/Analysis/Core/src/AODMerger.cxx
@@ -99,7 +99,6 @@ int main(int argc, char* argv[])
         auto metaDataCurrentFile = (TMap*)inputFile->Get("metaData");
         if (metaData == nullptr) {
           metaData = metaDataCurrentFile;
-          // outputFile->WriteObject(&metaData, "metaData");
           outputFile->cd();
           metaData->Write("metaData", TObject::kSingleKey);
         } else {