Bug 1568903 - Part 9: Implement the Promise.any proposal. r=jorendorff

As with AggregateError, `Promise.any` is only enabled in Nightly.

Now that everything is in place, the actual `Promise.any` implementation is
relatively straight forward. The only tricky part is probably just the
`ThrowAggregateError` function, when the async stack is created to give a
better stack trace.

Differential Revision: https://phabricator.services.mozilla.com/D51659

--HG--
rename : js/src/jit-test/tests/promise/promise-race-with-non-default-resolving.js => js/src/jit-test/tests/promise/promise-any-with-non-default-resolving.js
extra : moz-landing-system : lando

js/src/builtin/Promise.cpp

@@ -20,8 +20,10 @@
 #include "js/ForOfIterator.h"  // JS::ForOfIterator
 #include "js/PropertySpec.h"
 #include "util/Poison.h"
+#include "vm/ArrayObject.h"
 #include "vm/AsyncFunction.h"
 #include "vm/AsyncIteration.h"
+#include "vm/ErrorObject.h"
 #include "vm/GeneratorObject.h"
 #include "vm/Iteration.h"
 #include "vm/JSContext.h"
@@ -30,6 +32,7 @@
 
 #include "debugger/DebugAPI-inl.h"
 #include "vm/Compartment-inl.h"
+#include "vm/ErrorObject-inl.h"
 #include "vm/JSObject-inl.h"
 #include "vm/NativeObject-inl.h"
 
@@ -2389,22 +2392,27 @@ static MOZ_MUST_USE bool PerformPromiseAllSettled(
     JSContext* cx, PromiseForOfIterator& iterator, HandleObject C,
     Handle<PromiseCapability> resultCapability, bool* done);
 
+static MOZ_MUST_USE bool PerformPromiseAny(
+    JSContext* cx, PromiseForOfIterator& iterator, HandleObject C,
+    Handle<PromiseCapability> resultCapability, bool* done);
+
 static MOZ_MUST_USE bool PerformPromiseRace(
     JSContext* cx, PromiseForOfIterator& iterator, HandleObject C,
     Handle<PromiseCapability> resultCapability, bool* done);
 
-enum class CombinatorKind { All, AllSettled, Race };
+enum class CombinatorKind { All, AllSettled, Any, Race };
 
-// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// ES2020 draft rev e97c95d064750fb949b6778584702dd658cf5624
 //
 // Unified implementation of
 // 25.6.4.1 Promise.all ( iterable )
-// 25.6.4.3 Promise.race ( iterable )
+// 25.6.4.2 Promise.allSettled ( iterable )
+// 25.6.4.4 Promise.race ( iterable )
 //
-// Promise.allSettled (Stage 4 proposal)
-// https://tc39.github.io/proposal-promise-allSettled/
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
 //
-// Promise.allSettled ( iterable )
+// Promise.any ( iterable )
 static MOZ_MUST_USE bool CommonPromiseCombinator(JSContext* cx, CallArgs& args,
                                                  CombinatorKind kind) {
   HandleValue iterable = args.get(0);
@@ -2420,6 +2428,9 @@ static MOZ_MUST_USE bool CommonPromiseCombinator(JSContext* cx, CallArgs& args,
       case CombinatorKind::AllSettled:
         message = "Receiver of Promise.allSettled call";
         break;
+      case CombinatorKind::Any:
+        message = "Receiver of Promise.any call";
+        break;
       case CombinatorKind::Race:
         message = "Receiver of Promise.race call";
         break;
@@ -2453,6 +2464,9 @@ static MOZ_MUST_USE bool CommonPromiseCombinator(JSContext* cx, CallArgs& args,
       case CombinatorKind::AllSettled:
         message = "Argument of Promise.allSettled";
         break;
+      case CombinatorKind::Any:
+        message = "Argument of Promise.any";
+        break;
       case CombinatorKind::Race:
         message = "Argument of Promise.race";
         break;
@@ -2471,6 +2485,9 @@ static MOZ_MUST_USE bool CommonPromiseCombinator(JSContext* cx, CallArgs& args,
     case CombinatorKind::AllSettled:
       result = PerformPromiseAllSettled(cx, iter, C, promiseCapability, &done);
       break;
+    case CombinatorKind::Any:
+      result = PerformPromiseAny(cx, iter, C, promiseCapability, &done);
+      break;
     case CombinatorKind::Race:
       result = PerformPromiseRace(cx, iter, C, promiseCapability, &done);
       break;
@@ -2706,13 +2723,14 @@ static MOZ_MUST_USE JSObject* CommonStaticResolveRejectImpl(
 
 static bool IsPromiseSpecies(JSContext* cx, JSFunction* species);
 
-// ES2020 draft rev dc1e21c454bd316810be1c0e7af0131a2d7f38e9
+// ES2020 draft rev e97c95d064750fb949b6778584702dd658cf5624
 // 25.6.4.1.1 Runtime Semantics: PerformPromiseAll, steps 5-6 and step 8.
-// 25.6.4.3.1 Runtime Semantics: PerformPromiseRace, steps 3-5.
+// 25.6.4.2.1 Runtime Semantics: PerformPromiseAllSettled, steps 5-6 and step 8.
+// 25.6.4.4.1 Runtime Semantics: PerformPromiseRace, steps 3-5.
 //
-// Promise.allSettled (Stage 4 proposal)
-// https://tc39.github.io/proposal-promise-allSettled/
-// Runtime Semantics: PerformPromiseAllSettled, steps 5-6 and step 8.
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+// Runtime Semantics: PerformPromiseAny, steps 6-8.
 template <typename T>
 static MOZ_MUST_USE bool CommonPerformPromiseCombinator(
     JSContext* cx, PromiseForOfIterator& iterator, HandleObject C,
@@ -3316,8 +3334,8 @@ static MOZ_MUST_USE bool PerformPromiseRace(
 
 enum class PromiseAllSettledElementFunctionKind { Resolve, Reject };
 
-// Promise.allSettled (Stage 4 proposal)
-// https://tc39.github.io/proposal-promise-allSettled/
+// ES2020 draft rev e97c95d064750fb949b6778584702dd658cf5624
+// 25.6.4.2 Promise.allSettled ( iterable )
 //
 // Promise.allSettled Resolve Element Functions
 // Promise.allSettled Reject Element Functions
@@ -3325,8 +3343,8 @@ template <PromiseAllSettledElementFunctionKind Kind>
 static bool PromiseAllSettledElementFunction(JSContext* cx, unsigned argc,
                                              Value* vp);
 
-// Promise.allSettled (Stage 4 proposal)
-// https://tc39.github.io/proposal-promise-allSettled/
+// ES2020 draft rev e97c95d064750fb949b6778584702dd658cf5624
+// 25.6.4.2 Promise.allSettled ( iterable )
 //
 // Promise.allSettled ( iterable )
 static bool Promise_static_allSettled(JSContext* cx, unsigned argc, Value* vp) {
@@ -3334,8 +3352,8 @@ static bool Promise_static_allSettled(JSContext* cx, unsigned argc, Value* vp) {
   return CommonPromiseCombinator(cx, args, CombinatorKind::AllSettled);
 }
 
-// Promise.allSettled (Stage 4 proposal)
-// https://tc39.github.io/proposal-promise-allSettled/
+// ES2020 draft rev e97c95d064750fb949b6778584702dd658cf5624
+// 25.6.4.2 Promise.allSettled ( iterable )
 //
 // PerformPromiseAllSettled ( iteratorRecord, constructor, resultCapability )
 static MOZ_MUST_USE bool PerformPromiseAllSettled(
@@ -3521,6 +3539,224 @@ static bool PromiseAllSettledElementFunction(JSContext* cx, unsigned argc,
   return true;
 }
 
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// Promise.any ( iterable )
+static bool Promise_static_any(JSContext* cx, unsigned argc, Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  return CommonPromiseCombinator(cx, args, CombinatorKind::Any);
+}
+
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// Promise.any Reject Element Functions
+static bool PromiseAnyRejectElementFunction(JSContext* cx, unsigned argc,
+                                            Value* vp);
+
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// ThrowAggregateError ( errors )
+static void ThrowAggregateError(JSContext* cx,
+                                Handle<PromiseCombinatorElements> errors,
+                                HandleObject promise);
+
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// PerformPromiseAny ( iteratorRecord, constructor, resultCapability )
+static MOZ_MUST_USE bool PerformPromiseAny(
+    JSContext* cx, PromiseForOfIterator& iterator, HandleObject C,
+    Handle<PromiseCapability> resultCapability, bool* done) {
+  *done = false;
+
+  // Step 1.
+  MOZ_ASSERT(C->isConstructor());
+
+  // Step 2 (omitted).
+
+  // Step 3.
+  Rooted<PromiseCombinatorElements> errors(cx);
+  if (!NewPromiseCombinatorElements(cx, resultCapability, &errors)) {
+    return false;
+  }
+
+  // Step 4.
+  // Create our data holder that holds all the things shared across every step
+  // of the iterator. In particular, this holds the remainingElementsCount (as
+  // an integer reserved slot), the array of errors, and the reject function
+  // from our PromiseCapability.
+  Rooted<PromiseCombinatorDataHolder*> dataHolder(cx);
+  dataHolder = PromiseCombinatorDataHolder::New(
+      cx, resultCapability.promise(), errors, resultCapability.reject());
+  if (!dataHolder) {
+    return false;
+  }
+
+  // Step 5.
+  uint32_t index = 0;
+
+  auto getResolveAndReject = [cx, &resultCapability, &errors, &dataHolder,
+                              &index](MutableHandleValue resolveFunVal,
+                                      MutableHandleValue rejectFunVal) {
+    // Step 8.h.
+    if (!errors.pushUndefined(cx)) {
+      return false;
+    }
+
+    // Steps 8.j-p.
+    JSFunction* rejectFunc = NewPromiseCombinatorElementFunction(
+        cx, PromiseAnyRejectElementFunction, dataHolder, index);
+    if (!rejectFunc) {
+      return false;
+    }
+
+    // Step 8.q.
+    dataHolder->increaseRemainingCount();
+
+    // Step 8.s.
+    index++;
+    MOZ_ASSERT(index > 0);
+
+    resolveFunVal.setObject(*resultCapability.resolve());
+    rejectFunVal.setObject(*rejectFunc);
+    return true;
+  };
+
+  // BlockOnPromise fast path requires the passed onFulfilled function doesn't
+  // return an object value, because otherwise the skipped promise creation is
+  // detectable due to missing property lookups.
+  bool isDefaultResolveFn =
+      IsNativeFunction(resultCapability.resolve(), ResolvePromiseFunction);
+
+  // Steps 6-8.
+  if (!CommonPerformPromiseCombinator(
+          cx, iterator, C, resultCapability.promise(), done, isDefaultResolveFn,
+          getResolveAndReject)) {
+    return false;
+  }
+
+  // Step 8.d.ii.
+  int32_t remainingCount = dataHolder->decreaseRemainingCount();
+
+  // Step 8.d.iii.
+  if (remainingCount == 0) {
+    ThrowAggregateError(cx, errors, resultCapability.promise());
+    return false;
+  }
+
+  // Step 8.d.iv.
+  return true;
+}
+
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// Promise.any Reject Element Functions
+static bool PromiseAnyRejectElementFunction(JSContext* cx, unsigned argc,
+                                            Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  HandleValue xVal = args.get(0);
+
+  // Steps 1-5.
+  Rooted<PromiseCombinatorDataHolder*> data(cx);
+  uint32_t index;
+  if (PromiseCombinatorElementFunctionAlreadyCalled(args, &data, &index)) {
+    args.rval().setUndefined();
+    return true;
+  }
+
+  // Step 6.
+  Rooted<PromiseCombinatorElements> errors(cx);
+  if (!GetPromiseCombinatorElements(cx, data, &errors)) {
+    return false;
+  }
+
+  // Step 9.
+  if (!errors.setElement(cx, index, xVal)) {
+    return false;
+  }
+
+  // Steps 8, 10.
+  uint32_t remainingCount = data->decreaseRemainingCount();
+
+  // Step 11.
+  if (remainingCount == 0) {
+    // Step 7 (Adapted to work with PromiseCombinatorDataHolder's layout).
+    RootedObject rejectFun(cx, data->resolveOrRejectObj());
+    RootedObject promiseObj(cx, data->promiseObj());
+
+    ThrowAggregateError(cx, errors, promiseObj);
+
+    RootedValue reason(cx);
+    if (!MaybeGetAndClearException(cx, &reason)) {
+      return false;
+    }
+
+    if (!RunResolutionFunction(cx, rejectFun, reason, RejectMode, promiseObj)) {
+      return false;
+    }
+  }
+
+  // Step 12.
+  args.rval().setUndefined();
+  return true;
+}
+
+// Promise.any (Stage 3 proposal)
+// https://tc39.es/proposal-promise-any/
+//
+// ThrowAggregateError ( errors )
+static void ThrowAggregateError(JSContext* cx,
+                                Handle<PromiseCombinatorElements> errors,
+                                HandleObject promise) {
+  MOZ_ASSERT(!cx->isExceptionPending());
+
+  // Create the AggregateError in the same realm as the array object.
+  AutoRealm ar(cx, errors.unwrappedArray());
+
+  RootedObject allocationSite(cx);
+  mozilla::Maybe<JS::AutoSetAsyncStackForNewCalls> asyncStack;
+
+  // Provide a more useful error stack if possible: This function is typically
+  // called from Promise job queue, which doesn't have any JS frames on the
+  // stack. So when we create the AggregateError below, its stack property will
+  // be set to the empty string, which makes it harder to debug the error cause.
+  // To avoid this situation set-up an async stack based on the Promise
+  // allocation site, which should point to calling site of |Promise.any|.
+  if (promise->is<PromiseObject>()) {
+    allocationSite = promise->as<PromiseObject>().allocationSite();
+    if (allocationSite) {
+      asyncStack.emplace(
+          cx, allocationSite, "Promise.any",
+          JS::AutoSetAsyncStackForNewCalls::AsyncCallKind::IMPLICIT);
+    }
+  }
+
+  // AutoSetAsyncStackForNewCalls requires a new activation before it takes
+  // effect, so call into the self-hosting helper to set-up new call frames.
+  RootedValue error(cx);
+  if (!GetAggregateError(cx, JSMSG_PROMISE_ANY_REJECTION, &error)) {
+    return;
+  }
+
+  // |error| isn't guaranteed to be an AggregateErrorObject in case of OOM.
+  RootedSavedFrame stack(cx);
+  if (error.isObject() && error.toObject().is<AggregateErrorObject>()) {
+    auto* aggregateError = &error.toObject().as<AggregateErrorObject>();
+    aggregateError->setAggregateErrors(errors.unwrappedArray());
+
+    // Adopt the existing saved frames when present.
+    if (JSObject* errorStack = aggregateError->stack()) {
+      stack = &errorStack->as<SavedFrame>();
+    }
+  }
+
+  cx->setPendingException(error, stack);
+}
+
 // https://tc39.github.io/ecma262/#sec-promise.reject
 //
 // Unified implementation of
@@ -5866,6 +6102,9 @@ static const JSPropertySpec promise_properties[] = {
 static const JSFunctionSpec promise_static_methods[] = {
     JS_FN("all", Promise_static_all, 1, 0),
     JS_FN("allSettled", Promise_static_allSettled, 1, 0),
+#ifdef NIGHTLY_BUILD
+    JS_FN("any", Promise_static_any, 1, 0),
+#endif
     JS_FN("race", Promise_static_race, 1, 0),
     JS_FN("reject", Promise_reject, 1, 0),
     JS_FN("resolve", Promise_static_resolve, 1, 0),

js/src/builtin/Utilities.js

@@ -177,6 +177,15 @@ function GetTypeError(msg) {
     assert(false, "the catch block should've returned from this function.");
 }
 
+function GetAggregateError(msg) {
+    try {
+        FUN_APPLY(ThrowAggregateError, undefined, arguments);
+    } catch (e) {
+        return e;
+    }
+    assert(false, "the catch block should've returned from this function.");
+}
+
 function GetInternalError(msg) {
     try {
         FUN_APPLY(ThrowInternalError, undefined, arguments);

js/src/jit-test/tests/promise/promise-any-with-non-default-resolving.js

@@ -0,0 +1,58 @@
+// |jit-test| skip-if: !Promise.any
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+function neverCalled() {
+    // Quit with non-zero exit code to ensure a test suite error is shown,
+    // even when this function is called within promise handlers which normally
+    // swallow any exceptions.
+    quit(1);
+}
+
+var {promise, resolve} = newPromiseCapability();
+
+var getterCount = 0;
+
+class P extends Promise {
+    constructor(executor) {
+        var {promise, resolve, reject} = newPromiseCapability();
+
+        executor(function(v) {
+            // Resolve the promise.
+            resolve(v);
+
+            // But then return an object from the resolve function. This object
+            // must be treated as the resolution value for the otherwise
+            // skipped promise which gets created when Promise.prototype.then is
+            // called in PerformPromiseRace.
+            return {
+                get then() {
+                    getterCount++;
+                }
+            };
+        }, neverCalled);
+
+        return promise;
+    }
+
+    // Default to the standard Promise.resolve function, so we don't create
+    // another instance of this class when resolving the passed promise objects
+    // in Promise.race.
+    static resolve(v) {
+        return Promise.resolve(v);
+    }
+}
+
+P.any([promise]);
+
+resolve(0);
+
+drainJobQueue();
+
+assertEq(getterCount, 1);

js/src/js.msg

@@ -644,6 +644,7 @@ MSG_DEF(JSMSG_PROMISE_CAPABILITY_HAS_SOMETHING_ALREADY, 0, JSEXN_TYPEERR, "GetCa
 MSG_DEF(JSMSG_PROMISE_RESOLVE_FUNCTION_NOT_CALLABLE,    0, JSEXN_TYPEERR, "A Promise subclass passed a non-callable value as the resolve function.")
 MSG_DEF(JSMSG_PROMISE_REJECT_FUNCTION_NOT_CALLABLE,     0, JSEXN_TYPEERR, "A Promise subclass passed a non-callable value as the reject function.")
 MSG_DEF(JSMSG_PROMISE_ERROR_IN_WRAPPED_REJECTION_REASON,0, JSEXN_INTERNALERR, "Promise rejection value is a non-unwrappable cross-compartment wrapper.")
+MSG_DEF(JSMSG_PROMISE_ANY_REJECTION, 0, JSEXN_AGGREGATEERR, "No Promise in Promise.any was resolved")
 
 // Iterator
 MSG_DEF(JSMSG_RETURN_NOT_CALLABLE,     0, JSEXN_TYPEERR, "property 'return' of iterator is not callable")

js/src/jsexn.cpp

@@ -791,3 +791,11 @@ bool js::GetTypeError(JSContext* cx, unsigned errorNumber,
   return CallSelfHostedFunction(cx, cx->names().GetTypeError, NullHandleValue,
                                 args, error);
 }
+
+bool js::GetAggregateError(JSContext* cx, unsigned errorNumber,
+                           MutableHandleValue error) {
+  FixedInvokeArgs<1> args(cx);
+  args[0].set(Int32Value(errorNumber));
+  return CallSelfHostedFunction(cx, cx->names().GetAggregateError,
+                                NullHandleValue, args, error);
+}

js/src/jsexn.h

@@ -119,6 +119,8 @@ bool GetInternalError(JSContext* cx, unsigned errorNumber,
                       MutableHandleValue error);
 bool GetTypeError(JSContext* cx, unsigned errorNumber,
                   MutableHandleValue error);
+bool GetAggregateError(JSContext* cx, unsigned errorNumber,
+                       MutableHandleValue error);
 
 }  // namespace js
 

js/src/tests/non262/Promise/any-stack.js

@@ -0,0 +1,69 @@
+// |reftest| skip-if(!Promise.any)
+
+function toMessage(stack) {
+  // Provide the stack string in the error message for debugging.
+  return `[stack: ${stack.replace(/\n/g, "\\n")}]`;
+}
+
+// Test when AggregateError isn't created from a Promise Job.
+{
+  let p = Promise.any([]); // line 10
+
+  p.then(v => {
+    reportCompare(0, 1, "expected error");
+  }, e => {
+    assertEq(e.name, "AggregateError");
+    var {stack} = e;
+
+    assertEq(/^@.+any-stack.js:10/m.test(stack), true, toMessage(stack));
+  });
+}
+
+// Same as above, but now with surrounding function context.
+function testNoJobQueue() {
+  let p = Promise.any([]); // line 24
+
+  p.then(v => {
+    reportCompare(0, 1, "expected error");
+  }, e => {
+    assertEq(e.name, "AggregateError");
+    var {stack} = e;
+
+    assertEq(/^testNoJobQueue@.+any-stack.js:24/m.test(stack), true, toMessage(stack));
+  });
+}
+testNoJobQueue();
+
+// Test when AggregateError is created from a Promise Job.
+{
+  let rejected = Promise.reject(0);
+  let p = Promise.any([rejected]); // line 40
+
+  p.then(v => {
+    reportCompare(0, 1, "expected error");
+  }, e => {
+    assertEq(e.name, "AggregateError");
+    var {stack} = e;
+
+    assertEq(/^Promise.any\*@.+any-stack.js:40/m.test(stack), true, toMessage(stack));
+  });
+}
+
+// Same as above, but now with surrounding function context.
+function testFromJobQueue() {
+  let rejected = Promise.reject(0);
+  let p = Promise.any([rejected]); // line 55
+
+  p.then(v => {
+    reportCompare(0, 1, "expected error");
+  }, e => {
+    assertEq(e.name, "AggregateError");
+    var {stack} = e;
+
+    assertEq(/^Promise.any\*testFromJobQueue@.+any-stack.js:55/m.test(stack), true, toMessage(stack));
+  });
+}
+testFromJobQueue();
+
+if (typeof reportCompare === "function")
+  reportCompare(0, 0);

js/src/tests/non262/Promise/any.js

@@ -0,0 +1,78 @@
+// |reftest| skip-if(!Promise.any)
+
+// Smoke test for `Promise.any`, test262 should cover the function in
+// more detail.
+
+function expectedError() {
+  reportCompare(true, false, "expected error");
+}
+
+// Empty elements.
+Promise.any([]).then(expectedError, e => {
+  assertEq(e instanceof AggregateError, true);
+  assertEq(e.errors.length, 0);
+});
+
+// Single element.
+Promise.any([Promise.resolve(0)]).then(v => {
+  assertEq(v, 0);
+});
+Promise.any([Promise.reject(1)]).then(expectedError, e => {
+  assertEq(e instanceof AggregateError, true);
+  assertEq(e.errors.length, 1);
+  assertEq(e.errors[0], 1);
+});
+
+// Multiple elements.
+Promise.any([Promise.resolve(1), Promise.resolve(2)]).then(v => {
+  assertEq(v, 1);
+});
+Promise.any([Promise.resolve(3), Promise.reject(4)]).then(v => {
+  assertEq(v, 3);
+});
+Promise.any([Promise.reject(5), Promise.resolve(6)]).then(v => {
+  assertEq(v, 6);
+});
+Promise.any([Promise.reject(7), Promise.reject(8)]).then(expectedError, e => {
+  assertEq(e instanceof AggregateError, true);
+  assertEq(e.errors.length, 2);
+  assertEq(e.errors[0], 7);
+  assertEq(e.errors[1], 8);
+});
+
+// Cross-Realm tests.
+//
+// Note: When |g| is a cross-compartment global, Promise.any creates the errors
+// array and the AggregateError in |g|'s Realm. This doesn't follow the spec, but
+// the code in js/src/builtin/Promise.cpp claims this is useful when the Promise
+// compartment is less-privileged. This means for this test we can't use
+// assertDeepEq below, because the result array/error may have the wrong prototype.
+let g = newGlobal();
+
+if (typeof isSameCompartment !== "function") {
+  var isSameCompartment = SpecialPowers.Cu.getJSTestingFunctions().isSameCompartment;
+}
+
+// Test wrapping when no `Promise.any Reject Element Function` is called.
+Promise.any.call(g.Promise, []).then(expectedError, e => {
+  assertEq(e.name, "AggregateError");
+
+  assertEq(isSameCompartment(e, g), true);
+  assertEq(isSameCompartment(e.errors, g), true);
+
+  assertEq(e.errors.length, 0);
+});
+
+// Test wrapping in `Promise.any Reject Element Function`.
+Promise.any.call(g.Promise, [Promise.reject("err")]).then(expectedError, e => {
+  assertEq(e.name, "AggregateError");
+
+  assertEq(isSameCompartment(e, g), true);
+  assertEq(isSameCompartment(e.errors, g), true);
+
+  assertEq(e.errors.length, 1);
+  assertEq(e.errors[0], "err");
+});
+
+if (typeof reportCompare === "function")
+  reportCompare(0, 0);

js/src/vm/CommonPropertyNames.h

@@ -185,6 +185,7 @@
   MACRO(GeneratorReturn, GeneratorReturn, "GeneratorReturn")                   \
   MACRO(GeneratorThrow, GeneratorThrow, "GeneratorThrow")                      \
   MACRO(get, get, "get")                                                       \
+  MACRO(GetAggregateError, GetAggregateError, "GetAggregateError")             \
   MACRO(GetInternalError, GetInternalError, "GetInternalError")                \
   MACRO(getBigInt64, getBigInt64, "getBigInt64")                               \
   MACRO(getBigUint64, getBigUint64, "getBigUint64")                            \

js/src/vm/SelfHosting.cpp

@@ -391,6 +391,15 @@ static bool intrinsic_ThrowSyntaxError(JSContext* cx, unsigned argc,
   return false;
 }
 
+static bool intrinsic_ThrowAggregateError(JSContext* cx, unsigned argc,
+                                          Value* vp) {
+  CallArgs args = CallArgsFromVp(argc, vp);
+  MOZ_ASSERT(args.length() >= 1);
+
+  ThrowErrorWithType(cx, JSEXN_AGGREGATEERR, args);
+  return false;
+}
+
 static bool intrinsic_ThrowInternalError(JSContext* cx, unsigned argc,
                                          Value* vp) {
   CallArgs args = CallArgsFromVp(argc, vp);
@@ -2169,6 +2178,7 @@ static const JSFunctionSpec intrinsic_functions[] = {
     JS_FN("ThrowRangeError", intrinsic_ThrowRangeError, 4, 0),
     JS_FN("ThrowTypeError", intrinsic_ThrowTypeError, 4, 0),
     JS_FN("ThrowSyntaxError", intrinsic_ThrowSyntaxError, 4, 0),
+    JS_FN("ThrowAggregateError", intrinsic_ThrowAggregateError, 4, 0),
     JS_FN("ThrowInternalError", intrinsic_ThrowInternalError, 4, 0),
     JS_FN("GetErrorMessage", intrinsic_GetErrorMessage, 1, 0),
     JS_FN("CreateModuleSyntaxError", intrinsic_CreateModuleSyntaxError, 4, 0),