diff --git a/port/linux/.vscode/launch.json b/port/linux/.vscode/launch.json
index 56ddd162d..fcd1f2db0 100644
--- a/port/linux/.vscode/launch.json
+++ b/port/linux/.vscode/launch.json
@@ -23,7 +23,7 @@
                 // "--gtest_filter=except.try_import_except"
                 // "--gtest_filter=vm.test_cmodule_import_as"
                 // "--gtest_filter=vm.subsrc_import"
-                // "--gtest_filter=event.event_thread"
+                "--gtest_filter=event.event_thread3"
                 // "--gtest_filter=module.while_loop"
             ],
             "stopAtEntry": false,
diff --git a/port/linux/package/pikascript/main.py b/port/linux/package/pikascript/main.py
index 4b4f9d555..dff24d92a 100644
--- a/port/linux/package/pikascript/main.py
+++ b/port/linux/package/pikascript/main.py
@@ -1,6 +1,7 @@
 import PikaStdLib
 import PikaDebug
 import this
+from subsrc import mod1
 
 print('hello pikapython!')
 mem = PikaStdLib.MemChecker()
diff --git a/port/linux/package/pikascript/pikascript-lib/PikaStdDevice/pika_hal_SOFT_SPI.c b/port/linux/package/pikascript/pikascript-lib/PikaStdDevice/pika_hal_SOFT_SPI.c
index 2692f7334..d30231be9 100644
--- a/port/linux/package/pikascript/pikascript-lib/PikaStdDevice/pika_hal_SOFT_SPI.c
+++ b/port/linux/package/pikascript/pikascript-lib/PikaStdDevice/pika_hal_SOFT_SPI.c
@@ -63,7 +63,7 @@ int pika_hal_platform_SOFT_SPI_ioctl_enable(pika_dev* dev) {
     }
     pika_debug("SCK[0x%p] config", cfg->SCK);
     pika_hal_ioctl(cfg->SCK, PIKA_HAL_IOCTL_CONFIG, &cfg_SCK);
-    if (NULL != cfg->MOSI){
+    if (NULL != cfg->MOSI) {
         pika_debug("MOSI[0x%p] config", cfg->MOSI);
         pika_hal_ioctl(cfg->MOSI, PIKA_HAL_IOCTL_CONFIG, &cfg_MOSI);
     }
@@ -78,7 +78,7 @@ int pika_hal_platform_SOFT_SPI_ioctl_enable(pika_dev* dev) {
     }
     pika_debug("SCK[0x%p] enable", cfg->SCK);
     pika_hal_ioctl(cfg->SCK, PIKA_HAL_IOCTL_ENABLE);
-    if (NULL != cfg->MOSI){
+    if (NULL != cfg->MOSI) {
         pika_debug("MOSI[0x%p] enable", cfg->MOSI);
         pika_hal_ioctl(cfg->MOSI, PIKA_HAL_IOCTL_ENABLE);
     }
@@ -91,7 +91,7 @@ int pika_hal_platform_SOFT_SPI_ioctl_enable(pika_dev* dev) {
         _GPIO_write(cfg->CS, 1);
     }
     _GPIO_write(cfg->SCK, 1);
-    if (NULL != cfg->MOSI){
+    if (NULL != cfg->MOSI) {
         _GPIO_write(cfg->MOSI, 1);
     }
     return 0;
diff --git a/src/PikaObj.c b/src/PikaObj.c
index 31756bafe..eb5fa145a 100644
--- a/src/PikaObj.c
+++ b/src/PikaObj.c
@@ -3016,14 +3016,14 @@ PIKA_RES _do_pika_eventListener_send(PikaEventListener* self,
     if (pika_GIL_isInit()) {
         /* python thread is running */
         /* wait python thread get first lock */
-        while (1){
-            if (_VM_is_first_lock()){
+        while (1) {
+            if (_VM_is_first_lock()) {
                 break;
             }
-            if (pika_GIL_getBareLock() == 0){
+            if (g_PikaVMState.vm_cnt == 0) {
                 break;
             }
-            if (g_PikaVMState.vm_cnt == 0){
+            if (pika_GIL_getBareLock() == 0) {
                 break;
             }
             pika_platform_thread_yield();
diff --git a/src/PikaObj.h b/src/PikaObj.h
index 2ae76d45f..04e0900c7 100644
--- a/src/PikaObj.h
+++ b/src/PikaObj.h
@@ -777,7 +777,7 @@ const MethodProp floatMethod = {
 #define pika_class(_method) _method##NativeProp
 
 void _obj_updateProxyFlag(PikaObj* self);
-#define obj_setClass(_self, _method)                        \
+#define obj_setClass(_self, _method)                         \
     obj_setPtr((_self), "@p_", (void*)&pika_class(_method)); \
     _obj_updateProxyFlag((_self))
 
@@ -842,7 +842,6 @@ int pika_GIL_EXIT(void);
 int pika_GIL_ENTER(void);
 int pika_GIL_getBareLock(void);
 
-
 int32_t pika_debug_find_break_point_pc(char* pyFile, uint32_t pyLine);
 
 typedef PikaObj PikaList;
diff --git a/src/PikaVM.c b/src/PikaVM.c
index 6c3002fa2..755aac1bd 100644
--- a/src/PikaVM.c
+++ b/src/PikaVM.c
@@ -92,18 +92,15 @@ int pika_GIL_ENTER(void) {
     return ret;
 }
 
-int pika_GIL_getBareLock(void){
+int pika_GIL_getBareLock(void) {
     return g_pikaGIL.mutex.bare_lock;
 }
 
 int pika_GIL_EXIT(void) {
-    if (!g_pikaGIL.mutex.is_init) {
+    if (!g_pikaGIL.mutex.is_first_lock || !g_pikaGIL.mutex.is_init) {
         g_pikaGIL.mutex.bare_lock = 0;
         return 0;
     }
-    if (!g_pikaGIL.mutex.is_first_lock) {
-        return 0;
-    }
     return pika_thread_recursive_mutex_unlock(&g_pikaGIL);
 }
 
@@ -2658,6 +2655,15 @@ static void _OPT_ADD(OperatorInfo* op) {
         return;
     }
 #endif
+    // Check if either argument is a string and the other is not a string
+    if ((op->t1 == ARG_TYPE_STRING && op->t2 != ARG_TYPE_STRING) ||
+        (op->t2 == ARG_TYPE_STRING && op->t1 != ARG_TYPE_STRING)) {
+        PikaVMFrame_setErrorCode(op->vm, PIKA_RES_ERR_OPERATION_FAILED);
+        PikaVMFrame_setSysOut(
+            op->vm, "TypeError: unsupported operand + between str and non-str");
+        op->res = NULL;
+        return;
+    }
     if ((op->t1 == ARG_TYPE_STRING) && (op->t2 == ARG_TYPE_STRING)) {
         char* num1_s = NULL;
         char* num2_s = NULL;
diff --git a/src/PikaVersion.h b/src/PikaVersion.h
index 8720d3acd..99bb5f211 100644
--- a/src/PikaVersion.h
+++ b/src/PikaVersion.h
@@ -2,4 +2,4 @@
 #define PIKA_VERSION_MINOR 13
 #define PIKA_VERSION_MICRO 3
 
-#define PIKA_EDIT_TIME "2024/05/06 00:34:23"
+#define PIKA_EDIT_TIME "2024/05/15 10:48:43"
diff --git a/tools/pikaCompiler/rust-msc-latest-win10.exe b/tools/pikaCompiler/rust-msc-latest-win10.exe
index 24064a9bd..0cb3a4918 100644
Binary files a/tools/pikaCompiler/rust-msc-latest-win10.exe and b/tools/pikaCompiler/rust-msc-latest-win10.exe differ
diff --git a/tools/pikaCompiler/src/compiler.rs b/tools/pikaCompiler/src/compiler.rs
index 82d1e688e..465b6ae48 100644
--- a/tools/pikaCompiler/src/compiler.rs
+++ b/tools/pikaCompiler/src/compiler.rs
@@ -238,6 +238,23 @@ impl Compiler {
         Err(std::io::Error::from(std::io::ErrorKind::NotFound))
     }
 
+    // Check if a given path is a folder.
+    fn check_is_folder(&self, folder_name: &str) -> bool {
+        let folder_path = format!("{}{}", self.source_path, folder_name);
+        Compiler::is_folder(folder_path).is_ok()
+    }
+
+    // Function to check if the given path is a folder.
+    fn is_folder(path: String) -> io::Result<()> {
+        let new_path = transform_path(&path);
+        let path = Path::new(&new_path);
+        if path.exists() && path.is_dir() {
+            Ok(())
+        } else {
+            Err(io::Error::from(io::ErrorKind::NotFound))
+        }
+    }
+
     pub fn analyse_py_package_main(self: Compiler, file_name: String) -> Compiler {
         return self.__do_analyse_file(file_name, PackageType::PyPackageTop);
     }
@@ -272,6 +289,12 @@ impl Compiler {
     }
 
     pub fn import_module_ex(self, file_name: String, from_scan: bool) -> Compiler {
+        // Check for folder
+        if self.check_is_folder(&file_name) {
+            println!("    skip folder: {}{}...", self.source_path, file_name);
+            return self;
+        }
+
         // Check for py.o file.
         if self.try_open_file(&file_name, "py.o") {
             println!("    found {}{}.py.o...", self.source_path, file_name);