fix(editor): Store ScriptedContext on ScriptedObject for disposal (#12070) cb54233310

This PR hardens ScriptedContext teardown to eliminate Lua stack growth during ScriptedObject destruction and prevent teardown-time crashes.

Co-authored-by: Philip Chung <philterdesign@gmail.com>

Author: philter

.rive_head

@@ -1 +1 @@
-3afc336770a7664a2c6d0b4556d7b5ca9f8a8549
+cb54233310847138571ca99c90fcc9e528ffca05

include/rive/lua/rive_lua_libs.hpp

@@ -1211,15 +1211,13 @@ class ScriptedContext
 public:
     ScriptedContext(ScriptedObject*);
     ScriptedObject* scriptedObject() { return m_scriptedObject; }
+    void clearScriptedObject() { m_scriptedObject = nullptr; }
     static constexpr uint8_t luaTag = LUA_T_COUNT + 28;
     static constexpr const char* luaName = "Context";
     static constexpr bool hasMetatable = true;
-    void dispose() { m_disposed = true; }
-    bool disposed() { return m_disposed; }
 
 private:
     ScriptedObject* m_scriptedObject = nullptr;
-    bool m_disposed = false;
 };
 
 /// Wraps [`ListenerInvocation`] for `performAction` in scripted listener

include/rive/scripted/scripted_object.hpp

@@ -21,6 +21,7 @@ class DataContext;
 class ViewModelInstanceValue;
 class DataBindContainer;
 class ScriptedProperty;
+class ScriptedContext;
 
 class ScriptedObject : public FileAssetReferencer,
                        public CustomPropertyContainer,
@@ -29,6 +30,7 @@ class ScriptedObject : public FileAssetReferencer,
 protected:
     int m_self = 0;
     int m_context = 0;
+    ScriptedContext* m_contextPtr = nullptr;
     virtual void disposeScriptInputs();
 #ifdef WITH_RIVE_SCRIPTING
 #ifdef WITH_RIVE_TOOLS

src/lua/lua_scripted_context.cpp

@@ -26,8 +26,9 @@ static int context_namecall(lua_State* L)
     if (str != nullptr)
     {
         auto scriptedContext = lua_torive<ScriptedContext>(L, 1);
-        if (scriptedContext->disposed())
+        if (scriptedContext->scriptedObject() == nullptr)
         {
+            luaL_error(L, "context:%s() called on a disposed context", str);
             return 0;
         }
         switch (atom)

src/lua/rive_lua_libs.cpp

@@ -288,6 +288,7 @@ int rive_lua_pcall_with_context(lua_State* state,
 
 int rive_lua_pushRef(lua_State* state, int ref)
 {
+    lua_checkstack(state, 1);
     return lua_rawgeti(state, luaRegistryIndex, ref);
 }
 

src/scripted/scripted_object.cpp

@@ -251,11 +251,6 @@ bool ScriptedObject::scriptInit(ScriptingVM* vm)
     }
     else
     {
-        // Stack: [self]
-        lua_newrive<ScriptedContext>(L, this);
-        // Stack: [self, ScriptedContext]
-        m_context = lua_ref(L, -1);
-        rive_lua_pop(L, 1);
         // Stack: [self]
         m_self = lua_ref(L, -1);
 #ifdef WITH_RIVE_TOOLS
@@ -273,6 +268,11 @@ bool ScriptedObject::scriptInit(ScriptingVM* vm)
         }
         if (inits())
         {
+            // Stack: [self]
+            m_contextPtr = lua_newrive<ScriptedContext>(L, this);
+            // Stack: [self, ScriptedContext]
+            m_context = lua_ref(L, -1);
+            rive_lua_pop(L, 1);
             // Stack: [self]
             lua_getfield(L, -1, "init");
             // Stack: [self, field]
@@ -336,14 +336,18 @@ void ScriptedObject::disposeScriptInputs()
 
 void ScriptedObject::disposeScriptedContext()
 {
+    if (m_contextPtr != nullptr)
+    {
+        m_contextPtr->clearScriptedObject();
+        m_contextPtr = nullptr;
+    }
     if (m_context != 0)
     {
         lua_State* L = state();
-        rive_lua_pushRef(L, m_context);
-        auto scriptedContext = lua_torive<ScriptedContext>(L, -1);
-        scriptedContext->dispose();
-        rive_lua_pop(L, 1);
-        lua_unref(L, m_context);
+        if (L != nullptr)
+        {
+            lua_unref(L, m_context);
+        }
         m_context = 0;
     }
 }

tests/unit_tests/runtime/scripting/scripting_context_test.cpp

@@ -5,6 +5,7 @@
 #include "rive/animation/state_machine_instance.hpp"
 #include "rive/assets/image_asset.hpp"
 #include "rive_file_reader.hpp"
+#include <string>
 
 using namespace rive;
 
@@ -63,6 +64,32 @@ end
     }
 }
 
+TEST_CASE("Scripted Context errors when used after disposal", "[scripting]")
+{
+    ScriptingTest vm(
+        R"(
+function callMarkNeedsUpdate(context: Context)
+  context:markNeedsUpdate()
+end
+)");
+    ScriptedObjectTest scriptedObjectTest;
+    lua_State* L = vm.state();
+    auto top = lua_gettop(L);
+
+    lua_getglobal(L, "callMarkNeedsUpdate");
+    auto scriptedContext = lua_newrive<ScriptedContext>(L, &scriptedObjectTest);
+    scriptedContext->clearScriptedObject();
+    int result = lua_pcall(L, 1, 0, 0);
+    REQUIRE(result == LUA_ERRRUN);
+    const char* error = lua_tostring(L, -1);
+    REQUIRE(error != nullptr);
+    CHECK(std::string(error).find(
+              "context:markNeedsUpdate() called on a disposed context") !=
+          std::string::npos);
+    lua_pop(L, 1);
+    CHECK(top == lua_gettop(L));
+}
+
 TEST_CASE("script has access to user created view models via Data", "[silver]")
 {
     rive::SerializingFactory silver;