From c279445ec07bc2b14893bd6f878260d4b7a65bda Mon Sep 17 00:00:00 2001
From: Stefan Wunsch <stefan.wunsch@cern.ch>
Date: Tue, 28 Jan 2020 16:22:22 +0100
Subject: [PATCH] [ROOT-10508] Fix TTreeProcessorMT for unnamed chain as friend
* Retrieves correctly the name of the trees building the chain if the
chain itself does not has a name. This happens if the default
constructor for TChain is used and the name of the tree is retrieved
via the string given to `TChain::AddFile("file.root/treeName")`.
* This does not fix the issue entirely since the FriendInfo needs a
refactoring. The FriendInfo assumes that in a chain each tree has the
same name, which could not hold true.
---
tree/treeplayer/src/TTreeProcessorMT.cxx | 39 +++++++++++++++---------
1 file changed, 25 insertions(+), 14 deletions(-)
diff --git a/tree/treeplayer/src/TTreeProcessorMT.cxx b/tree/treeplayer/src/TTreeProcessorMT.cxx
index 0823eadf448..edb1a607be0 100644
--- a/tree/treeplayer/src/TTreeProcessorMT.cxx
+++ b/tree/treeplayer/src/TTreeProcessorMT.cxx
@@ -328,26 +328,37 @@ Internal::FriendInfo TTreeProcessorMT::GetFriendInfo(TTree &tree)
for (auto fr : *friends) {
const auto frTree = static_cast<TFriendElement *>(fr)->GetTree();
+ const bool isChain = frTree->IsA() == TChain::Class();
- // Check if friend tree has an alias
- const auto realName = frTree->GetName();
- const auto alias = tree.GetFriendAlias(frTree);
- if (alias) {
- friendNames.emplace_back(std::make_pair(realName, std::string(alias)));
- } else {
- friendNames.emplace_back(std::make_pair(realName, ""));
- }
-
- // Store the file names of the friend tree
friendFileNames.emplace_back();
auto &fileNames = friendFileNames.back();
- const bool isChain = tree.IsA() == TChain::Class();
+
+ // Check if friend tree/chain has an alias
+ const auto alias_c = tree.GetFriendAlias(frTree);
+ const std::string alias = alias_c != nullptr ? alias_c : "";
+
if (isChain) {
- const auto frChain = static_cast<TChain *>(frTree);
- for (auto f : *(frChain->GetListOfFiles())) {
+ // Note that each TChainElement returned by chain.GetListOfFiles has a name
+ // equal to the tree name of this TChain and a title equal to the filename.
+ // Accessing the information like this ensures that we get the correct
+ // filenames and treenames if the treename is given as part of the filename
+ // via chain.AddFile(file.root/myTree) and as well if the tree name is given
+ // in the constructor via TChain(myTree) and a file is added later by chain.AddFile(file.root).
+
+ // Get name of the trees building the chain
+ const auto chainFiles = static_cast<TChain*>(frTree)->GetListOfFiles();
+ const auto realName = chainFiles->First()->GetName();
+ friendNames.emplace_back(std::make_pair(realName, alias));
+ // Get filenames stored in the title member
+ for (auto f : *chainFiles) {
fileNames.emplace_back(f->GetTitle());
}
} else {
+ // Get name of the tree
+ const auto realName = frTree->GetName();
+ friendNames.emplace_back(std::make_pair(realName, alias));
+
+ // Get filename
const auto f = frTree->GetCurrentFile();
if (!f)
throw std::runtime_error("Friend trees with no associated file are not supported.");
@@ -549,4 +560,4 @@ unsigned int TTreeProcessorMT::GetMaxTasksPerFilePerWorker()
void TTreeProcessorMT::SetMaxTasksPerFilePerWorker(unsigned int maxTasksPerFile)
{
fgMaxTasksPerFilePerWorker = maxTasksPerFile;
-}
\ No newline at end of file
+}
--
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