From 4e35aa7f827cae308455b726ef4bb0514206cf73 Mon Sep 17 00:00:00 2001
From: Chris Jones <chrisdjones15@gmail.com>
Date: Sat, 26 Mar 2022 18:46:20 -0500
Subject: [PATCH] Make JobReport::reportReadBranches thread safe

CRAB jobs have been failing to parse the job report because of
this race condition.
---
 FWCore/MessageLogger/interface/JobReport.h | 2 +-
 FWCore/MessageLogger/src/JobReport.cc      | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/FWCore/MessageLogger/interface/JobReport.h b/FWCore/MessageLogger/interface/JobReport.h
index aa0ab8308429a..2effaf489f5e6 100644
--- a/FWCore/MessageLogger/interface/JobReport.h
+++ b/FWCore/MessageLogger/interface/JobReport.h
@@ -255,7 +255,7 @@ namespace edm {
       std::map<std::string, long long> readBranches_;
       std::map<std::string, long long> readBranchesSecFile_;
       tbb::concurrent_unordered_map<std::string, AtomicLongLong> readBranchesSecSource_;
-      bool printedReadBranches_;
+      std::atomic<bool> printedReadBranches_;
       std::vector<InputFile>::size_type lastOpenedPrimaryInputFile_;
       edm::propagate_const<std::ostream*> ost_;
     };
diff --git a/FWCore/MessageLogger/src/JobReport.cc b/FWCore/MessageLogger/src/JobReport.cc
index 78e5537d22303..bfdcdeada0a9d 100644
--- a/FWCore/MessageLogger/src/JobReport.cc
+++ b/FWCore/MessageLogger/src/JobReport.cc
@@ -567,9 +567,9 @@ namespace edm {
   }
 
   void JobReport::reportReadBranches() {
-    if (impl_->printedReadBranches_)
+    bool expected = false;
+    if (not impl_->printedReadBranches_.compare_exchange_strong(expected, true))
       return;
-    impl_->printedReadBranches_ = true;
     if (impl_->ost_) {
       std::ostream& ost = *(impl_->ost_);
       ost << "<ReadBranches>\n";