fix: for-await-of 收尾 return 抛错恢复原始异常值

crates/oxide_vm/src/vm_dispatch_misc.rs

@@ -739,14 +739,22 @@ impl Vm {
         }
         let iter_obj = unsafe { &*iterator.as_js_object_ptr() };
         let return_si = self.kernel_core.perm_interner().intern("return").0;
-        let return_fn = self.ordinary_get(iter_obj, return_si, iterator)?;
+        let return_fn = match self.ordinary_get(iter_obj, return_si, iterator) {
+            Ok(v) => v,
+            // return getter 抛出：恢复原始异常值并就地展开，使外围 try/catch 可捕获。
+            Err(e) => return self.throw_for_of_close_error(&e),
+        };
         if !return_fn.is_object() {
             return Ok(());
         }
         if !unsafe { &*return_fn.as_js_object_ptr() }.is_function() {
             return Ok(());
         }
-        let inner = self.call_function_sync(return_fn, iterator, &[])?;
+        let inner = match self.call_function_sync(return_fn, iterator, &[]) {
+            Ok(v) => v,
+            // return() 抛出：恢复原始异常值并就地展开，使外围 try/catch 可捕获。
+            Err(e) => return self.throw_for_of_close_error(&e),
+        };
         if !inner.is_object() {
             return self.raise_type_error("iterator return() result is not an object");
         }
@@ -862,6 +870,23 @@ impl Vm {
         self.unwind()
     }
 
+    /// for-await-of 收尾抛错（return getter 或 return() 调用）：恢复原始异常值并就地
+    /// 展开，使外围 try/catch 可捕获。本函数入口已弹出本迭代器条目，故展开路径不得
+    /// 再弹 for-of 栈（与 throw_for_of_error_value 的唯一区别）。
+    ///
+    /// 直接 unwind 而非经 raise_call_error：后者以 native_call_depth 门控展开，
+    /// 异步函数恢复期深度恒大于零会误判为不展开，使异常绕过循环内 catch 直接
+    /// 拒绝 capability promise。
+    fn throw_for_of_close_error(&mut self, msg: &str) -> Result<(), String> {
+        let exc = self
+            .last_uncaught_value
+            .take()
+            .unwrap_or_else(|| oxide_builtins::error::create_from_text(self, msg));
+        self.exception_value = Some(exc);
+        self.pending_error_kind = Some(self.thrown_error_kind(exc));
+        self.unwind()
+    }
+
     pub(crate) fn dispatch_for_of_close(&mut self) -> Result<(), String> {
         vm_trace!("FOR_OF_CLOSE");
         let Some(entry) = self.iters.pop_for_of() else {

crates/oxide_vm/tests/async_tests.rs

@@ -239,6 +239,48 @@ fn for_await_of_return_escape_defers_async_close() {
     );
 }
 
+#[test]
+fn for_await_of_close_return_getter_throw_propagates_original() {
+    // 收尾时 return 的 getter 抛出：外围 catch 须收到原始抛出值，
+    // 不得是重建的 Error 对象。
+    assert_eq!(
+        eval(
+            "let caught;\
+             const it={[Symbol.asyncIterator](){return{next(){return Promise.resolve({value:1,done:false})},get return(){throw 'ret-getter';}}}};\
+             (async()=>{ try { for await (const x of it) { break; } } catch (e) { caught = e; } return 'caught:' + caught; })()"
+        ),
+        "\"caught:ret-getter\""
+    );
+}
+
+#[test]
+fn for_await_of_close_return_call_throw_propagates_original() {
+    // 收尾时 return() 调用抛出：外围 catch 须收到原始抛出值。
+    assert_eq!(
+        eval(
+            "let caught;\
+             const it={[Symbol.asyncIterator](){return{next(){return Promise.resolve({value:1,done:false})},return(){throw 'ret-call';}}}};\
+             (async()=>{ try { for await (const x of it) { break; } } catch (e) { caught = e; } return 'caught:' + caught; })()"
+        ),
+        "\"caught:ret-call\""
+    );
+}
+
+#[test]
+fn for_await_of_close_throw_object_identity_preserved() {
+    // 收尾时 return() 抛出对象：外围 catch 收到的须是同一对象（身份保留），
+    // 证明原始异常值经异常通道传播而非按文本重建。
+    assert_eq!(
+        eval(
+            "let caught;\
+             const marker={tag:'x'};\
+             const it={[Symbol.asyncIterator](){return{next(){return Promise.resolve({value:1,done:false})},return(){throw marker;}}}};\
+             (async()=>{ try { for await (const x of it) { break; } } catch (e) { caught = e; } return caught === marker ? 'same' : 'diff:' + caught; })()"
+        ),
+        "\"same\""
+    );
+}
+
 // ── class/object 生成器方法（异步） ──
 
 // class async 生成器方法：yield 顺序与 done 收敛。顶层 then 链驱动