From 84521ef08a700702019e51e0e0bbee4870d3fe6e Mon Sep 17 00:00:00 2001
From: krzys-h <krzys_h@interia.pl>
Date: Sat, 23 Jan 2016 21:33:58 +0100
Subject: [PATCH] Fixed CBotClass::FreeLock crash on some compilers

---
 src/CBot/CBotClass.cpp | 7 ++++++-
 src/CBot/CBotClass.h   | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/CBot/CBotClass.cpp b/src/CBot/CBotClass.cpp
index a3ee74df..dc99761a 100644
--- a/src/CBot/CBotClass.cpp
+++ b/src/CBot/CBotClass.cpp
@@ -148,7 +148,12 @@ void CBotClass::FreeLock(CBotProgram* prog)
             pClass->m_lockCurrentCount = 0;
         }
 
-        pClass->m_lockProg.erase(std::remove(pClass->m_lockProg.begin(), pClass->m_lockProg.end(), prog));
+        // Note: erasing an end iterator is undefined behaviour
+        auto it = std::remove(pClass->m_lockProg.begin(), pClass->m_lockProg.end(), prog);
+        if (it != pClass->m_lockProg.end())
+        {
+            pClass->m_lockProg.erase(it);
+        }
     }
 }
 
diff --git a/src/CBot/CBotClass.h b/src/CBot/CBotClass.h
index a826911a..03e61ef7 100644
--- a/src/CBot/CBotClass.h
+++ b/src/CBot/CBotClass.h
@@ -387,7 +387,7 @@ private:
 
     //! How many times the program currently holding the lock called Lock()
     int m_lockCurrentCount = 0;
-    //! Programs waiting for lock
+    //! Programs waiting for lock. m_lockProg[0] is the program currently holding the lock, if any
     std::deque<CBotProgram*> m_lockProg{};
 };