From 77cdf0953cd484912929a458976408b276d71c0c Mon Sep 17 00:00:00 2001
From: Tomas Dado <tomas.dado@cern.ch>
Date: Fri, 15 Dec 2023 18:05:37 +0100
Subject: [PATCH] Fixing issue 14225 Fixing a crash in
 HistoToWorkspaceFactoryFast.cxx where a parameter that was globally set to be
 constant was not found a given region, but the code was still accessing the
 parameter even when it was nullptr. Now the parameter is set to constant only
 when found in a given region. Also demoting the error to warning as this does
 not always indicate a wrong setup.

---
 roofit/histfactory/src/HistoToWorkspaceFactoryFast.cxx | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/roofit/histfactory/src/HistoToWorkspaceFactoryFast.cxx b/roofit/histfactory/src/HistoToWorkspaceFactoryFast.cxx
index 70b9c2643f4a0..bc40db8f0023b 100644
--- a/roofit/histfactory/src/HistoToWorkspaceFactoryFast.cxx
+++ b/roofit/histfactory/src/HistoToWorkspaceFactoryFast.cxx
@@ -1253,11 +1253,12 @@ RooArgList HistoToWorkspaceFactoryFast::createObservables(const TH1 *hist, RooWo
     for(unsigned int i=0; i<systToFix.size(); ++i){
       RooRealVar* temp = proto.var(systToFix.at(i));
       if(!temp) {
-        cxcoutE(HistFactory) << "could not find variable " << systToFix.at(i)
+        cxcoutW(HistFactory) << "could not find variable " << systToFix.at(i)
             << " could not set it to constant" << endl;
+      } else {
+        // set the parameter constant
+        temp->setConstant();
       }
-      // set the parameter constant
-      temp->setConstant();
     }
 
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