From a603c0c57c9d259827fdfb954d2a67b493e341e0 Mon Sep 17 00:00:00 2001
From: Alberto Caliva <alberto.caliva@cern.ch>
Date: Thu, 23 Jul 2026 21:06:42 +0200
Subject: [PATCH 1/3] Fix seg fault caused by stale particle indices after
 coalescence from HF decays

---
 MC/config/common/external/generator/CoalescencePythia8.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/MC/config/common/external/generator/CoalescencePythia8.h b/MC/config/common/external/generator/CoalescencePythia8.h
index 7e4abc53e..270184a73 100644
--- a/MC/config/common/external/generator/CoalescencePythia8.h
+++ b/MC/config/common/external/generator/CoalescencePythia8.h
@@ -152,6 +152,9 @@ bool CoalescencePythia8(Pythia8::Event& event, std::vector<unsigned int> inputPd
       for (int iN{0}; iN < neutrons[iC].size(); ++iN) {
         if (nuclearMask & (1 << kDeuteron)) {
           coalHappened |= doCoal(event, iC, pdgList[kDeuteron], massList[kDeuteron], trivialCoal, coalescenceRadius, nuclFromDecay, protons[iC][iP], neutrons[iC][iN]);
+          if (nuclFromDecay && coalHappened) {
+            return true;
+          }
         }
         if (nuclearMask & (1 << kTriton)) {
           for (int iN2{iN + 1}; iN2 < neutrons[iC].size(); ++iN2) {

From 359c8f96fc193dd8df806ab13c4bd0dcdbf29052 Mon Sep 17 00:00:00 2001
From: Alberto Caliva <alberto.caliva@cern.ch>
Date: Mon, 27 Jul 2026 19:25:51 +0200
Subject: [PATCH 2/3] Prevent invalid particle index access after decay
 coalescence

---
 .../common/external/generator/CoalescencePythia8.h   | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/MC/config/common/external/generator/CoalescencePythia8.h b/MC/config/common/external/generator/CoalescencePythia8.h
index 270184a73..378dcc0b4 100644
--- a/MC/config/common/external/generator/CoalescencePythia8.h
+++ b/MC/config/common/external/generator/CoalescencePythia8.h
@@ -159,22 +159,34 @@ bool CoalescencePythia8(Pythia8::Event& event, std::vector<unsigned int> inputPd
         if (nuclearMask & (1 << kTriton)) {
           for (int iN2{iN + 1}; iN2 < neutrons[iC].size(); ++iN2) {
             coalHappened |= doCoal(event, iC, pdgList[kTriton], massList[kTriton], trivialCoal, coalescenceRadius, nuclFromDecay, protons[iC][iP], neutrons[iC][iN], neutrons[iC][iN2]);
+            if (nuclFromDecay && coalHappened) {
+              return true;
+            }
           }
         }
         if (nuclearMask & (1 << kHe3)) {
           for (int iP2{iP + 1}; iP2 < protons[iC].size(); ++iP2) {
             coalHappened |= doCoal(event, iC, pdgList[kHe3], massList[kHe3], trivialCoal, coalescenceRadius, nuclFromDecay, protons[iC][iP], protons[iC][iP2], neutrons[iC][iN]);
+            if (nuclFromDecay && coalHappened) {
+              return true;
+            }
           }
         }
         if (nuclearMask & (1 << kHyperTriton)) {
           for (int iL{0}; iL < lambdas[iC].size(); ++iL) {
             coalHappened |= doCoal(event, iC, pdgList[kHyperTriton], massList[kHyperTriton], trivialCoal, coalescenceRadius, nuclFromDecay, protons[iC][iP], neutrons[iC][iN], lambdas[iC][iL]);
+            if (nuclFromDecay && coalHappened) {
+              return true;
+            }
           }
         }
         if (nuclearMask & (1 << kHe4)) {
           for (int iP2{iP + 1}; iP2 < protons[iC].size(); ++iP2) {
             for (int iN2{iN + 1}; iN2 < neutrons[iC].size(); ++iN2) {
               coalHappened |= doCoal(event, iC, pdgList[kHe4], massList[kHe4], trivialCoal, coalescenceRadius, nuclFromDecay, protons[iC][iP], protons[iC][iP2], neutrons[iC][iN], neutrons[iC][iN2]);
+              if (nuclFromDecay && coalHappened) {
+                return true;
+              }
             }
           }
         }

From b6a67b84e25745685db5d50dd52b0954f1d80121 Mon Sep 17 00:00:00 2001
From: Alberto Caliva <alberto.caliva@cern.ch>
Date: Tue, 28 Jul 2026 21:00:37 +0200
Subject: [PATCH 3/3] restarting the CI

---
 MC/config/common/external/generator/CoalescencePythia8.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MC/config/common/external/generator/CoalescencePythia8.h b/MC/config/common/external/generator/CoalescencePythia8.h
index 378dcc0b4..bfe462521 100644
--- a/MC/config/common/external/generator/CoalescencePythia8.h
+++ b/MC/config/common/external/generator/CoalescencePythia8.h
@@ -107,6 +107,7 @@ bool doCoal(Pythia8::Event& event, int charge, int pdgCode, float mass, bool tri
 bool CoalescencePythia8(Pythia8::Event& event, std::vector<unsigned int> inputPdgList = {}, bool trivialCoal = false, double coalMomentum = 0.4, int firstDauID = -1, int lastDauId = -1, float maxRapidity = 1.)
 {
   const double coalescenceRadius{0.5 * 1.122462 * coalMomentum};
+
   // if coalescence from a heavy hadron, loop only between firstDauID and lastDauID
   int loopStart = firstDauID > -1 ? firstDauID : 0;
   int loopEnd = lastDauId > -1 ? lastDauId : event.size() - 1;