Merge branch 'clang.TrigConfIO-20210106' into 'master'

TrigConfIO, TrigCostAnalysis: Fix clang warnings.

See merge request atlas/athena!39514

Trigger/TrigConfiguration/TrigConfIO/src/JsonFileWriterHLT.cxx

 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "TrigConfIO/JsonFileWriterHLT.h"
@@ -36,12 +36,12 @@ TrigConf::JsonFileWriterHLT::writeJsonFile(const std::string & filename, const H
    }
 
    json sequencers({});
-   for ( const auto [seqName, algsList]: menu.sequencers() ) {
+   for ( const auto& [seqName, algsList]: menu.sequencers() ) {
       json jSeq( algsList );
       sequencers[seqName] = jSeq;
    }
    json streams({});
-   for ( const auto stream: menu.streams() ) {
+   for ( const auto& stream: menu.streams() ) {
       json jStream({});
       jStream["name"] = stream["name"];
       jStream["type"] = stream["type"];

Trigger/TrigCost/TrigCostAnalysis/Root/TableConstructorBase.cxx

 /*
-  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
 */
 
 #include "../TrigCostAnalysis/TableConstructorBase.h"
@@ -75,7 +75,7 @@ void TableConstructorBase::getHistograms(const std::string& name) {
     TObject* obj = key->ReadObj();
     if ( obj->IsA()->InheritsFrom( TH1::Class() ) ) {
       bool found = false;
-      for (const TString exp : m_expectedHistograms) {
+      for (const TString& exp : m_expectedHistograms) {
         const TString objName( obj->GetName() );
         const TString expName = TString(name) + "_" + exp;
         if (objName.EndsWith(expName)) {
@@ -86,8 +86,8 @@ void TableConstructorBase::getHistograms(const std::string& name) {
       }
       if (!found) {
         msg() << MSG::ERROR << "Was not expecting histogram " << obj->GetName() << endmsg;
-        for (const TString exp : m_expectedHistograms) {
-          const TString expName = TString(name) + "_" + exp;
+        for (const TString& exp : m_expectedHistograms) {
+          const TString& expName = TString(name) + "_" + exp;
           msg() << MSG::ERROR << "  -- Expected " << expName << endmsg;
         }
       }