From cc9852d212e9bb8cbd0cb4567dd8d6f89feb24a6 Mon Sep 17 00:00:00 2001
From: mmusich <marco.musich@cern.ch>
Date: Fri, 28 May 2021 16:40:17 +0200
Subject: [PATCH] protect the case in which there is no input histogram to
 harvest

---
 .../SiStripChannelGain/src/SiStripGainsPCLHarvester.cc         | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CalibTracker/SiStripChannelGain/src/SiStripGainsPCLHarvester.cc b/CalibTracker/SiStripChannelGain/src/SiStripGainsPCLHarvester.cc
index 6537b4e41930f..9d83de340bd53 100644
--- a/CalibTracker/SiStripChannelGain/src/SiStripGainsPCLHarvester.cc
+++ b/CalibTracker/SiStripChannelGain/src/SiStripGainsPCLHarvester.cc
@@ -258,6 +258,9 @@ void SiStripGainsPCLHarvester::gainQualityMonitor(DQMStore::IBooker& ibooker_,
 
     if (Gain != 1.) {
       std::vector<MonitorElement*> charge_histos = APVGain::FetchMonitor(new_charge_histos, DetId, tTopo_);
+
+      if (!Charge_Vs_Index)
+        continue;
       TH2S* chvsidx = (Charge_Vs_Index)->getTH2S();
       int bin = chvsidx->GetXaxis()->FindBin(Index);
       TH1D* Proj = chvsidx->ProjectionY("proj", bin, bin);