Add exception to rejection logic in `generic_call` (#32950)

* exception in JS Promise

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

* EXCEPTION_TO_REJECTION on generic_call

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

* PromiseRejectionEvent should handle promise as object

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

* expectations

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

---------

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>

4 files changed, 54 insertions, 29 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index fa77c516abb..154ec01c7ae 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -1870,13 +1870,17 @@ class MethodDefiner(PropertyDefiner):
             else:
                 selfHostedName = "0 as *const libc::c_char"
                 if m.get("methodInfo", True):
+                    if m.get("returnsPromise", False):
+                        exceptionToRejection = "true"
+                    else:
+                        exceptionToRejection = "false"
                     identifier = m.get("nativeName", m["name"])
                     # Go through an intermediate type here, because it's not
                     # easy to tell whether the methodinfo is a JSJitInfo or
                     # a JSTypedMethodJitInfo here.  The compiler knows, though,
                     # so let it do the work.
                     jitinfo = "&%s_methodinfo as *const _ as *const JSJitInfo" % identifier
-                    accessor = "Some(generic_method)"
+                    accessor = f"Some(generic_method::<{exceptionToRejection}>)"
                 else:
                     if m.get("returnsPromise", False):
                         jitinfo = "&%s_methodinfo" % m.get("nativeName", m["name"])
@@ -1977,10 +1981,14 @@ class AttrDefiner(PropertyDefiner):
                 accessor = 'get_' + self.descriptor.internalNameFor(attr.identifier.name)
                 jitinfo = "0 as *const JSJitInfo"
             else:
+                if attr.type.isPromise():
+                    exceptionToRejection = "true"
+                else:
+                    exceptionToRejection = "false"
                 if attr.hasLegacyLenientThis():
-                    accessor = "generic_lenient_getter"
+                    accessor = f"generic_lenient_getter::<{exceptionToRejection}>"
                 else:
-                    accessor = "generic_getter"
+                    accessor = f"generic_getter::<{exceptionToRejection}>"
                 jitinfo = "&%s_getterinfo" % self.descriptor.internalNameFor(attr.identifier.name)
 
             return ("JSNativeWrapper { op: Some(%(native)s), info: %(info)s }"
diff --git a/components/script/dom/bindings/utils.rs b/components/script/dom/bindings/utils.rs
index 764e604620c..07424ff6d3f 100644
--- a/components/script/dom/bindings/utils.rs
+++ b/components/script/dom/bindings/utils.rs
@@ -466,7 +466,7 @@ pub unsafe fn delete_property_by_id(
     JS_DeletePropertyById(cx, object, id, bp)
 }
 
-unsafe fn generic_call(
+unsafe fn generic_call<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
@@ -488,7 +488,11 @@ unsafe fn generic_call(
     let thisobj = args.thisv();
     if !thisobj.get().is_null_or_undefined() && !thisobj.get().is_object() {
         throw_invalid_this(cx, proto_id);
-        return false;
+        return if EXCEPTION_TO_REJECTION {
+            exception_to_promise(cx, args.rval())
+        } else {
+            false
+        };
     }
 
     rooted!(in(cx) let obj = if thisobj.get().is_object() {
@@ -507,7 +511,11 @@ unsafe fn generic_call(
                 return true;
             } else {
                 throw_invalid_this(cx, proto_id);
-                return false;
+                return if EXCEPTION_TO_REJECTION {
+                    exception_to_promise(cx, args.rval())
+                } else {
+                    false
+                };
             }
         },
     };
@@ -522,30 +530,30 @@ unsafe fn generic_call(
 }
 
 /// Generic method of IDL interface.
-pub unsafe extern "C" fn generic_method(
+pub unsafe extern "C" fn generic_method<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
 ) -> bool {
-    generic_call(cx, argc, vp, false, CallJitMethodOp)
+    generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, false, CallJitMethodOp)
 }
 
 /// Generic getter of IDL interface.
-pub unsafe extern "C" fn generic_getter(
+pub unsafe extern "C" fn generic_getter<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
 ) -> bool {
-    generic_call(cx, argc, vp, false, CallJitGetterOp)
+    generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, false, CallJitGetterOp)
 }
 
 /// Generic lenient getter of IDL interface.
-pub unsafe extern "C" fn generic_lenient_getter(
+pub unsafe extern "C" fn generic_lenient_getter<const EXCEPTION_TO_REJECTION: bool>(
     cx: *mut JSContext,
     argc: libc::c_uint,
     vp: *mut JSVal,
 ) -> bool {
-    generic_call(cx, argc, vp, true, CallJitGetterOp)
+    generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, true, CallJitGetterOp)
 }
 
 unsafe extern "C" fn call_setter(
@@ -569,7 +577,7 @@ pub unsafe extern "C" fn generic_setter(
     argc: libc::c_uint,
     vp: *mut JSVal,
 ) -> bool {
-    generic_call(cx, argc, vp, false, call_setter)
+    generic_call::<false>(cx, argc, vp, false, call_setter)
 }
 
 /// Generic lenient setter of IDL interface.
@@ -578,7 +586,7 @@ pub unsafe extern "C" fn generic_lenient_setter(
     argc: libc::c_uint,
     vp: *mut JSVal,
 ) -> bool {
-    generic_call(cx, argc, vp, true, call_setter)
+    generic_call::<false>(cx, argc, vp, true, call_setter)
 }
 
 unsafe extern "C" fn instance_class_has_proto_at_depth(
diff --git a/components/script/dom/promiserejectionevent.rs b/components/script/dom/promiserejectionevent.rs
index 64e548493f2..fe907b010b4 100644
--- a/components/script/dom/promiserejectionevent.rs
+++ b/components/script/dom/promiserejectionevent.rs
@@ -2,10 +2,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use std::ptr::NonNull;
 use std::rc::Rc;
 
 use dom_struct::dom_struct;
-use js::jsapi::Heap;
+use js::jsapi::{Heap, JSObject};
 use js::jsval::JSVal;
 use js::rust::{HandleObject, HandleValue};
 use servo_atoms::Atom;
@@ -27,18 +28,18 @@ use crate::script_runtime::JSContext;
 #[dom_struct]
 pub struct PromiseRejectionEvent {
     event: Event,
-    #[ignore_malloc_size_of = "Rc"]
-    promise: Rc<Promise>,
-    #[ignore_malloc_size_of = "Defined in rust-mozjs"]
+    #[ignore_malloc_size_of = "Defined in mozjs"]
+    promise: Heap<*mut JSObject>,
+    #[ignore_malloc_size_of = "Defined in mozjs"]
     reason: Heap<JSVal>,
 }
 
 impl PromiseRejectionEvent {
     #[allow(crown::unrooted_must_root)]
-    fn new_inherited(promise: Rc<Promise>) -> Self {
+    fn new_inherited() -> Self {
         PromiseRejectionEvent {
             event: Event::new_inherited(),
-            promise,
+            promise: Heap::default(),
             reason: Heap::default(),
         }
     }
@@ -51,7 +52,15 @@ impl PromiseRejectionEvent {
         promise: Rc<Promise>,
         reason: HandleValue,
     ) -> DomRoot<Self> {
-        Self::new_with_proto(global, None, type_, bubbles, cancelable, promise, reason)
+        Self::new_with_proto(
+            global,
+            None,
+            type_,
+            bubbles,
+            cancelable,
+            promise.promise_obj(),
+            reason,
+        )
     }
 
     #[allow(crown::unrooted_must_root)]
@@ -61,14 +70,15 @@ impl PromiseRejectionEvent {
         type_: Atom,
         bubbles: EventBubbles,
         cancelable: EventCancelable,
-        promise: Rc<Promise>,
+        promise: HandleObject,
         reason: HandleValue,
     ) -> DomRoot<Self> {
         let ev = reflect_dom_object_with_proto(
-            Box::new(PromiseRejectionEvent::new_inherited(promise)),
+            Box::new(PromiseRejectionEvent::new_inherited()),
             global,
             proto,
         );
+        ev.promise.set(promise.get());
 
         {
             let event = ev.upcast::<Event>();
@@ -87,7 +97,6 @@ impl PromiseRejectionEvent {
         init: RootedTraceableBox<PromiseRejectionEventBinding::PromiseRejectionEventInit>,
     ) -> Fallible<DomRoot<Self>> {
         let reason = init.reason.handle();
-        let promise = init.promise.clone();
         let bubbles = EventBubbles::from(init.parent.bubbles);
         let cancelable = EventCancelable::from(init.parent.cancelable);
 
@@ -97,7 +106,7 @@ impl PromiseRejectionEvent {
             Atom::from(type_),
             bubbles,
             cancelable,
-            promise,
+            init.promise.handle(),
             reason,
         );
         Ok(event)
@@ -106,8 +115,8 @@ impl PromiseRejectionEvent {
 
 impl PromiseRejectionEventMethods for PromiseRejectionEvent {
     // https://html.spec.whatwg.org/multipage/#dom-promiserejectionevent-promise
-    fn Promise(&self) -> Rc<Promise> {
-        self.promise.clone()
+    fn Promise(&self, _cx: JSContext) -> NonNull<JSObject> {
+        NonNull::new(self.promise.get()).unwrap()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-promiserejectionevent-reason
diff --git a/components/script/dom/webidls/PromiseRejectionEvent.webidl b/components/script/dom/webidls/PromiseRejectionEvent.webidl
index 70d11b1ff33..46ecbc21718 100644
--- a/components/script/dom/webidls/PromiseRejectionEvent.webidl
+++ b/components/script/dom/webidls/PromiseRejectionEvent.webidl
@@ -7,11 +7,11 @@
 [Exposed=(Window,Worker)]
 interface PromiseRejectionEvent : Event {
   [Throws] constructor(DOMString type, PromiseRejectionEventInit eventInitDict);
-  readonly attribute Promise<any> promise;
+  readonly attribute object promise;
   readonly attribute any reason;
 };
 
 dictionary PromiseRejectionEventInit : EventInit {
-  required Promise<any> promise;
+  required object promise;
   any reason;
 };