From ce11a1dfa91a184d4c641f0060dbaafceaa77ee5 Mon Sep 17 00:00:00 2001
From: David Cernat <davidcernat@gmail.com>
Date: Sun, 28 Jan 2018 21:19:03 +0200
Subject: [PATCH] [Client] Fix potential invalid pointer when storing cell
 unloads

Notably, builds of the client done with Clang were crashing on startup before this.
---
 apps/openmw/mwmp/LocalPlayer.cpp |  2 +-
 apps/openmw/mwmp/LocalPlayer.hpp |  2 +-
 apps/openmw/mwworld/scene.cpp    | 13 ++++++++++++-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/apps/openmw/mwmp/LocalPlayer.cpp b/apps/openmw/mwmp/LocalPlayer.cpp
index 5973ffea3..56a426807 100644
--- a/apps/openmw/mwmp/LocalPlayer.cpp
+++ b/apps/openmw/mwmp/LocalPlayer.cpp
@@ -1544,7 +1544,7 @@ void LocalPlayer::clearCurrentContainer()
     currentContainer.mpNum = 0;
 }
 
-void LocalPlayer::storeCellState(ESM::Cell cell, int stateType)
+void LocalPlayer::storeCellState(const ESM::Cell& cell, int stateType)
 {
     std::vector<CellState>::iterator iter;
 
diff --git a/apps/openmw/mwmp/LocalPlayer.hpp b/apps/openmw/mwmp/LocalPlayer.hpp
index 6f1dc9e07..1900b07b4 100644
--- a/apps/openmw/mwmp/LocalPlayer.hpp
+++ b/apps/openmw/mwmp/LocalPlayer.hpp
@@ -91,7 +91,7 @@ namespace mwmp
         void clearCellStates();
         void clearCurrentContainer();
 
-        void storeCellState(ESM::Cell cell, int stateType);
+        void storeCellState(const ESM::Cell& cell, int stateType);
         void storeCurrentContainer(const MWWorld::Ptr& container);
 
         void playAnimation();
diff --git a/apps/openmw/mwworld/scene.cpp b/apps/openmw/mwworld/scene.cpp
index 35161dca2..58e6200a7 100644
--- a/apps/openmw/mwworld/scene.cpp
+++ b/apps/openmw/mwworld/scene.cpp
@@ -243,6 +243,17 @@ namespace MWWorld
         std::cout << "Unloading cell\n";
         ListAndResetObjectsVisitor visitor;
 
+        /*
+            Start of tes3mp addition
+
+            Set a const pointer to the iterator's ESM::Cell here, because
+            (*iter)->getCell() can become invalid later down
+        */
+        const ESM::Cell* cell = (*iter)->getCell();
+        /*
+            End of tes3mp addition
+        */
+
         (*iter)->forEach<ListAndResetObjectsVisitor>(visitor);
         for (std::vector<MWWorld::Ptr>::const_iterator iter2 (visitor.mObjects.begin());
             iter2!=visitor.mObjects.end(); ++iter2)
@@ -276,7 +287,7 @@ namespace MWWorld
 
             Store a cell unload for the LocalPlayer
         */
-        mwmp::Main::get().getLocalPlayer()->storeCellState(*(*iter)->getCell(), mwmp::CellState::UNLOAD);
+        mwmp::Main::get().getLocalPlayer()->storeCellState(*cell, mwmp::CellState::UNLOAD);
         /*
             End of tes3mp addition
         */