Handle failure in KeyAccumulator::GetKeys

It turns out that KeyAccumulator::GetKeys will fail if the object it is
operating on is a Proxy with an ownKeys() or getOwnPropertyDescriptor()
trap that throws. Handle this case in
Isolate::GetImportAssertionsFromArgument by bailing out early.

Bug: v8:11730
Change-Id: I363bf2d218f6ba7eeb2001cd644f5529901fdb3e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2875541Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Dan Clark <daniec@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#74417}

src/execution/isolate.cc

@@ -4328,11 +4328,15 @@ MaybeHandle<FixedArray> Isolate::GetImportAssertionsFromArgument(
   Handle<JSReceiver> import_assertions_object_receiver =
       Handle<JSReceiver>::cast(import_assertions_object);
 
-  Handle<FixedArray> assertion_keys =
-      KeyAccumulator::GetKeys(import_assertions_object_receiver,
-                              KeyCollectionMode::kOwnOnly, ENUMERABLE_STRINGS,
-                              GetKeysConversion::kConvertToString)
-          .ToHandleChecked();
+  Handle<FixedArray> assertion_keys;
+  if (!KeyAccumulator::GetKeys(import_assertions_object_receiver,
+                               KeyCollectionMode::kOwnOnly, ENUMERABLE_STRINGS,
+                               GetKeysConversion::kConvertToString)
+           .ToHandle(&assertion_keys)) {
+    // This happens if the assertions object is a Proxy whose ownKeys() or
+    // getOwnPropertyDescriptor() trap throws.
+    return MaybeHandle<FixedArray>();
+  }
 
   // The assertions will be passed to the host in the form: [key1,
   // value1, key2, value2, ...].

test/mjsunit/harmony/modules-import-assertions-dynamic-12.mjs

+// Copyright 2021 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --harmony-import-assertions
+
+let result1;
+let result2;
+
+let badAssertProxy1 = new Proxy({}, { ownKeys() { throw "bad ownKeys!"; } });
+import('./modules-skip-1.mjs', { assert: badAssertProxy1 }).then(
+    () => assertUnreachable('Should have failed due to throwing ownKeys'),
+    error => result1 = error);
+
+let badAssertProxy2 = new Proxy(
+    {foo: "bar"},
+    { getOwnPropertyDescriptor() { throw "bad getOwnPropertyDescriptor!"; } });
+import('./modules-skip-1.mjs', { assert: badAssertProxy2 }).then(
+    () => assertUnreachable(
+        'Should have failed due to throwing getOwnPropertyDescriptor'),
+    error => result2 = error);
+
+%PerformMicrotaskCheckpoint();
+
+assertEquals('bad ownKeys!', result1);
+assertEquals('bad getOwnPropertyDescriptor!', result2);
\ No newline at end of file