Fix uninitialized context annex slot

src/context.rs

@@ -322,6 +322,9 @@ impl Context {
  slot: i32,
  data: *mut c_void,
  ) {
+ // Initialize the annex when slot count > INTERNAL_SLOT_COUNT.
+ self.get_annex_mut(&mut *v8__Context__GetIsolate(self), true);
+
  v8__Context__SetAlignedPointerInEmbedderData(
  self,
  slot + Self::INTERNAL_SLOT_COUNT,

tests/test_api.rs

@@ -11478,3 +11478,23 @@ fn microtask_queue_new() {
  // TODO(bartlomieju): add more tests once we have Context::New() bindings
  // https://github.com/denoland/rusty_v8/issues/1438
 }
+
+#[test]
+fn clear_slots_annex_uninitialized() {
+ let _setup_guard = setup::parallel_test();
+ let mut isolate = v8::Isolate::new(Default::default());
+
+ let mut scope = v8::HandleScope::new(&mut isolate);
+
+ let context = v8::Context::new(&mut scope);
+
+ let r = 0;
+ // This would increase slot count without initializing the annex.
+ unsafe {
+ context.set_aligned_pointer_in_embedder_data(1, &r as *const _ as *mut _);
+ }
+
+ // This was trying to deallocate a garbage value when the annex was not
+ // initialized.
+ context.clear_all_slots(&mut scope);
+}