fix: check for exceptions during promise polling

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fixed cross-thread stack overflow false positives in parallel mode by updating stack baseline before QuickJS C entry points
+- Fixed promise polling not returning Ready variant when exception occurs
 - Fixed iterators to use correct IteratorPrototype chain
 - Fixed a latent ABI layout vulnerability in `JS_NewPromiseCapability` FFI boundary by replacing tuple with strictly compatible array
 

core/src/context/ctx.rs

@@ -261,6 +261,11 @@ impl<'js> Ctx<'js> {
         }
     }
 
+    /// Returns true if there is a pending JavaScript exception.
+    pub fn has_exception(&self) -> bool {
+        unsafe { qjs::JS_HasException(self.ctx.as_ptr()) }
+    }
+
     /// Throws a JavaScript value as a new exception.
     /// Always returns `Error::Exception`;
     pub fn throw(&self, value: Value<'js>) -> Error {

core/src/value/promise.rs

@@ -190,6 +190,13 @@ where
             return Poll::Ready(x);
         }
 
+        // Check for pending exception (e.g., from interrupt handler).
+        // If there's a pending exception, the promise will never settle,
+        // so return the error instead of hanging forever.
+        if this.promise.ctx.has_exception() {
+            return Poll::Ready(Err(Error::Exception));
+        }
+
         if this.state.is_none() {
             let inner = Rc::new(RefCell::new(cx.waker().clone()));
             this.state = Some(inner.clone());