1454512 - rust is_symbol predicate broken on amd64

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P2)

Description

[Robin Templeton [:terpri]]

The is_symbol predicate in the Rust bindings doesn't work correctly on 64-bit systems. It compares the entire value against a shifted type tag, similar to the predicates for null and undefined, but it should ignore the value's payload (the symbol pointer).

Comment 1

[Robin Templeton [:terpri]]

Attachment: Fix JS::Value's is_symbol predicate.

Comment 2

[Robin Templeton [:terpri]]

Comment on attachment 8968357 [details] [diff] [review]
Fix JS::Value's is_symbol predicate.

Extract the type tag from the value in is_symbol and add a test case for it.

Comment 3

[Steve Fink [:sfink] [:s:]]

Comment on attachment 8968357 [details] [diff] [review]
Fix JS::Value's is_symbol predicate.

Review of attachment 8968357 [details] [diff] [review]:
-----------------------------------------------------------------

Nice, with a patch and everything. Thanks!

::: js/rust/tests/value.rs
@@ +26,5 @@
> +        );
> +        rooted!(in(cx) let mut rval = UndefinedValue());
> +        assert!(rt.evaluate_script(global.handle(), "Symbol('test')",
> +                                   "test", 1, rval.handle_mut()).is_ok());
> +        assert!(rval.is_symbol());

Can you add a negative test as well? A string seems best.

Comment 4

[Robin Templeton [:terpri]]

Attachment: Fix JS::Value's is_symbol predicate.

Comment 5

[Robin Templeton [:terpri]]

(In reply to Steve Fink [:sfink] [:s:] (PTO Apr9-12) from comment #3)
> Comment on attachment 8968357 [details] [diff] [review]
> Fix JS::Value's is_symbol predicate.
> 
> Review of attachment 8968357 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> Nice, with a patch and everything. Thanks!
> 
> ::: js/rust/tests/value.rs
> @@ +26,5 @@
> > +        );
> > +        rooted!(in(cx) let mut rval = UndefinedValue());
> > +        assert!(rt.evaluate_script(global.handle(), "Symbol('test')",
> > +                                   "test", 1, rval.handle_mut()).is_ok());
> > +        assert!(rval.is_symbol());
> 
> Can you add a negative test as well? A string seems best.

Sure, added in the new patch. (the tests could also be merged into a single #[test] function if that is better style)

Comment 6

[Steve Fink [:sfink] [:s:]]

(In reply to Robin Templeton from comment #5)
> Sure, added in the new patch. (the tests could also be merged into a single
> #[test] function if that is better style)

I have no clue, I've never looked at a rust test before. I have no issue with landing this as-is, though. Thanks!

Comment 7

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 8968768 [details] [diff] [review]
Fix JS::Value's is_symbol predicate.

Please use checkin-needed, it works better with the automated bug marking tools.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/fd6fc6aa6448
Fix JS::Value's is_symbol predicate. r=sfink

Comment 9

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/fd6fc6aa6448