Restore legacy bool get behavior: remove non-strict type check

Agent-Logs-Url: https://github.com/kunitoki/LuaBridge3/sessions/e6bc5e3f-455b-498f-8e99-d7eea2410da8

Co-authored-by: kunitoki <707032+kunitoki@users.noreply.github.com>

Author: Copilot

Distribution/LuaBridge/LuaBridge.h

@@ -4059,13 +4059,8 @@ struct Stack<bool>
 
     [[nodiscard]] static TypeResult<bool> get(lua_State* L, int index)
     {
-        const auto type = lua_type(L, index);
-
 #if LUABRIDGE_STRICT_STACK_CONVERSIONS
-        if (type != LUA_TBOOLEAN)
-            return makeErrorCode(ErrorCode::InvalidTypeCast);
-#else
-        if (type != LUA_TBOOLEAN && type != LUA_TNIL)
+        if (lua_type(L, index) != LUA_TBOOLEAN)
             return makeErrorCode(ErrorCode::InvalidTypeCast);
 #endif
 

Source/LuaBridge/detail/Stack.h

@@ -176,13 +176,8 @@ struct Stack<bool>
 
     [[nodiscard]] static TypeResult<bool> get(lua_State* L, int index)
     {
-        const auto type = lua_type(L, index);
-
 #if LUABRIDGE_STRICT_STACK_CONVERSIONS
-        if (type != LUA_TBOOLEAN)
-            return makeErrorCode(ErrorCode::InvalidTypeCast);
-#else
-        if (type != LUA_TBOOLEAN && type != LUA_TNIL)
+        if (lua_type(L, index) != LUA_TBOOLEAN)
             return makeErrorCode(ErrorCode::InvalidTypeCast);
 #endif
 

Tests/Source/StackTests.cpp

@@ -190,29 +190,42 @@ TEST_F(StackTests, BoolStackOverflow)
 
 TEST_F(StackTests, BoolInvalidType)
 {
-    // Non-boolean types are rejected even in non-strict mode
+#if !LUABRIDGE_STRICT_STACK_CONVERSIONS
+    // Non-strict mode: any Lua value is accepted via lua_toboolean
     {
         (void)luabridge::Stack<int>::push(L, 0);
         auto result = luabridge::Stack<bool>::get(L, -1);
-        ASSERT_FALSE(result);
+        ASSERT_TRUE(result);
+        EXPECT_TRUE(*result); // integer 0 is truthy in Lua
     }
 
     {
         (void)luabridge::Stack<int>::push(L, 42);
         auto result = luabridge::Stack<bool>::get(L, -1);
-        ASSERT_FALSE(result);
+        ASSERT_TRUE(result);
+        EXPECT_TRUE(*result);
     }
 
-#if !LUABRIDGE_STRICT_STACK_CONVERSIONS
-    // nil converts to false in non-strict mode
     {
         (void)luabridge::Stack<std::nullptr_t>::push(L, nullptr);
         auto result = luabridge::Stack<bool>::get(L, -1);
         ASSERT_TRUE(result);
-        EXPECT_FALSE(*result);
+        EXPECT_FALSE(*result); // nil is falsy
     }
 #else
-    // nil is rejected in strict mode
+    // Strict mode: only LUA_TBOOLEAN is accepted
+    {
+        (void)luabridge::Stack<int>::push(L, 0);
+        auto result = luabridge::Stack<bool>::get(L, -1);
+        ASSERT_FALSE(result);
+    }
+
+    {
+        (void)luabridge::Stack<int>::push(L, 42);
+        auto result = luabridge::Stack<bool>::get(L, -1);
+        ASSERT_FALSE(result);
+    }
+
     {
         (void)luabridge::Stack<std::nullptr_t>::push(L, nullptr);
         auto result = luabridge::Stack<bool>::get(L, -1);

Tests/Source/Tests.cpp

@@ -1243,11 +1243,18 @@ TEST_F(LuaBridgeTest, BooleanNoValue)
             .endClass()
         .endNamespace();
 
-    // Calling with no argument must fail: missing bool argument is LUA_TNONE, not a valid bool
+#if !LUABRIDGE_STRICT_STACK_CONVERSIONS
+    // Non-strict mode: no value at the argument index is accepted as false via lua_toboolean
+    runLua("local foo = test.ConstructibleFromBool(); result = foo:val()");
+    ASSERT_TRUE(result().isBool());
+    EXPECT_FALSE(result<bool>());
+#else
+    // Strict mode: missing bool argument must fail
 #if LUABRIDGE_HAS_EXCEPTIONS
     EXPECT_THROW(runLua("local foo = test.ConstructibleFromBool(); result = foo:val()"), std::runtime_error);
 #else
     EXPECT_FALSE(runLua("local foo = test.ConstructibleFromBool(); result = foo:val()"));
+#endif
 #endif
 
     // Passing false explicitly must work