Ensure Object type in dynamic import() Runtime Semantics

[dandclark]

In the Runtime Semantics for the version of dynamic import() that takes an assertions argument, the second argRef and the assertionsObj are not guaranteed to be Objects. e.g:

import("./foo", 42);
import("./foo", { assert: 42 });

But, Get() and EnumerableOwnPropertyNames both assert that the argument to them is an Object.

This change adds checks that these are of Type Object, and reject the promise with a TypeError if either is not.

assertionsObj is still allowed to be undefined. This will be useful if we use the options bag for other things such as evaluator attributes, where a missing assertionsObj shouldn't result in failure:

import('./foo", { with: { transformA: "value" } });

[bmeck]

No concerns if you throw. Problems around polluting the value via prototype aren't possible.

…

On Thu, Apr 29, 2021, 6:19 PM Dan Clark ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In spec.html <#108 (comment)> : > + 1. <ins>If Type(_arg_) is not Object, then</ins> + 1. <ins>Perform ! Call(_promiseCapability_.[[Reject]], *undefined*, &laquo; a newly created *TypeError* object &raquo;).</ins> This was discussed in April's meeting and it seems like there was pretty broad agreement that throwing for non-Object, rather than converting ToObject, is the direction we want to go. This matches what ECMA 402 is doing with GetOption() (link <https://github.com/tc39/notes/blob/master/meetings/2020-09/sept-22.md#getoption-in-ecma-262> ). @bmeck <https://github.com/bmeck> you mentioned that you had varied opinions on whether to reject or not based on whether we pull off the prototype (or something along those lines -- I didn't quite follow at the time). You said that you wanted to follow up offline, so I wanted to give you a chance to chime in here in case there was any concern you wanted to raise before I go ahead and land this PR. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#108 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABZJI33CYAGD3SRAVVG353TLHSRJANCNFSM4V77TAQA> .