Console command "reload lua"

apps/openmw/mwbase/luamanager.hpp

@@ -59,6 +59,9 @@ namespace MWBase
 
         // Should be called before loading. The map is used to fix refnums if the order of content files was changed.
         virtual void setContentFileMapping(const std::map<int, int>&) = 0;
+
+        // Drops script cache and reloads all scripts. Calls `onSave` and `onLoad` for every script.
+        virtual void reloadAllScripts() = 0;
     };
 
 }

apps/openmw/mwgui/console.cpp

@@ -20,6 +20,7 @@
 #include "../mwbase/scriptmanager.hpp"
 #include "../mwbase/windowmanager.hpp"
 #include "../mwbase/world.hpp"
+#include "../mwbase/luamanager.hpp"
 
 #include "../mwworld/esmstore.hpp"
 #include "../mwworld/class.hpp"

apps/openmw/mwlua/luamanagerimp.cpp

@@ -334,4 +334,30 @@ namespace MWLua
         scripts->setSerializer(mLocalSerializer.get());
     }
 
+    void LuaManager::reloadAllScripts()
+    {
+        Log(Debug::Info) << "Reload Lua";
+        mLua.dropScriptCache();
+
+        {  // Reload global scripts
+            ESM::LuaScripts data;
+            mGlobalScripts.save(data);
+            mGlobalScripts.removeAllScripts();
+            for (const std::string& path : mGlobalScriptList)
+                if (mGlobalScripts.addNewScript(path))
+                    Log(Debug::Info) << "Global script restarted: " << path;
+            mGlobalScripts.load(data, false);
+        }
+
+        for (const auto& [id, ptr] : mWorldView.getObjectRegistry()->mObjectMapping)
+        {  // Reload local scripts
+            LocalScripts* scripts = ptr.getRefData().getLuaScripts();
+            if (scripts == nullptr)
+                continue;
+            ESM::LuaScripts data;
+            scripts->save(data);
+            scripts->load(data, true);
+        }
+    }
+
 }

apps/openmw/mwlua/luamanagerimp.hpp

@@ -62,6 +62,9 @@ namespace MWLua
         void loadLocalScripts(const MWWorld::Ptr& ptr, const ESM::LuaScripts& data) override;
         void setContentFileMapping(const std::map<int, int>& mapping) override { mContentFileMapping = mapping; }
 
+        // Drops script cache and reloads all scripts. Calls `onSave` and `onLoad` for every script.
+        void reloadAllScripts() override;
+
     private:
         LocalScripts* createLocalScripts(const MWWorld::Ptr& ptr);
 

apps/openmw/mwlua/object.hpp

@@ -47,6 +47,7 @@ namespace MWLua
         friend class Object;
         friend class GObject;
         friend class LObject;
+        friend class LuaManager;
 
         bool mChanged = false;
         int64_t mUpdateCounter = 0;

apps/openmw/mwscript/docs/vmformat.txt

@@ -480,5 +480,6 @@ op 0x200031d: StartScript, explicit
 op 0x200031e: GetDistance
 op 0x200031f: GetDistance, explicit
 op 0x2000320: Help
+op 0x2000321: ReloadLua
 
-opcodes 0x2000321-0x3ffffff unused
+opcodes 0x2000322-0x3ffffff unused

apps/openmw/mwscript/miscextensions.cpp

@@ -28,6 +28,7 @@
 #include "../mwbase/scriptmanager.hpp"
 #include "../mwbase/soundmanager.hpp"
 #include "../mwbase/world.hpp"
+#include "../mwbase/luamanager.hpp"
 
 #include "../mwworld/class.hpp"
 #include "../mwworld/player.hpp"
@@ -169,8 +170,6 @@ namespace MWScript
                 void execute (Interpreter::Runtime& runtime) override
                 {
                     MWWorld::Ptr ptr = R()(runtime);
-                    if(!ptr.isEmpty() && !ptr.mRef->mData.isEnabled())
-                        ptr.mRef->mData.mPhysicsPostponed = false;
                     MWBase::Environment::get().getWorld()->enable (ptr);
                 }
         };
@@ -1599,6 +1598,17 @@ namespace MWScript
                 }
         };
 
+        class OpReloadLua : public Interpreter::Opcode0
+        {
+            public:
+
+                void execute (Interpreter::Runtime& runtime) override
+                {
+                    MWBase::Environment::get().getLuaManager()->reloadAllScripts();
+                    runtime.getContext().report("All Lua scripts are reloaded");
+                }
+        };
+
         void installOpcodes (Interpreter::Interpreter& interpreter)
         {
             interpreter.installSegment5 (Compiler::Misc::opcodeMenuMode, new OpMenuMode);
@@ -1719,6 +1729,7 @@ namespace MWScript
             interpreter.installSegment5 (Compiler::Misc::opcodeRepairedOnMeExplicit, new OpRepairedOnMe<ExplicitRef>);
             interpreter.installSegment5 (Compiler::Misc::opcodeToggleRecastMesh, new OpToggleRecastMesh);
             interpreter.installSegment5 (Compiler::Misc::opcodeHelp, new OpHelp);
+            interpreter.installSegment5 (Compiler::Misc::opcodeReloadLua, new OpReloadLua);
         }
     }
 }

components/compiler/extensions0.cpp

@@ -338,6 +338,7 @@ namespace Compiler
             extensions.registerFunction ("repairedonme", 'l', "S", opcodeRepairedOnMe, opcodeRepairedOnMeExplicit);
             extensions.registerInstruction ("togglerecastmesh", "", opcodeToggleRecastMesh);
             extensions.registerInstruction ("help", "", opcodeHelp);
+            extensions.registerInstruction ("reloadlua", "", opcodeReloadLua);
         }
     }
 

components/compiler/opcodes.hpp

@@ -319,6 +319,7 @@ namespace Compiler
         const int opcodeGetDisabledExplicit = 0x200031c;
         const int opcodeStartScriptExplicit = 0x200031d;
         const int opcodeHelp = 0x2000320;
+        const int opcodeReloadLua = 0x2000321;
     }
 
     namespace Sky

docs/source/reference/lua-scripting/overview.rst

@@ -114,6 +114,13 @@ Finally :ref:`register <Lua scripting>` it in ``openmw.cfg``:
 
 Now every time the player presses "X" on a keyboard, a message is shown.
 
+Hot reloading
+=============
+
+It is possible to modify a script without restarting OpenMW. To apply changes open in-game console and run the command ``reloadlua``.
+It will restart all Lua scripts using `onSave and onLoad`_ handlers the same way as if the game was saved and loaded.
+It works only with existing ``*.lua`` files that are not packed to any archives. Adding new scripts or modifying ``*.omwscripts`` files always requires restarting the game.
+
 Script structure
 ================