1231647 - Duplicate export check doesn't work for const and let bindings

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jon Coppeard (:jonco)]

These are not currently added to the exportedNames list.

Let/const bindings will generate a SyntaxError if they duplicate the name of an existing binding, but this is not enough to catch all errors.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: check-duplicate-export-let

Patch to add exported let/const names to the exported names list and add tests.

Comment 2

[Shu-yu Guo [:shu]]

Comment on attachment 8697245 [details] [diff] [review]
check-duplicate-export-let

Review of attachment 8697245 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/frontend/Parser.cpp
@@ +5052,5 @@
> +template<>
> +bool
> +Parser<SyntaxParseHandler>::addExportNamesForDeclaration(Node node)
> +{
> +    JS_ALWAYS_FALSE(abortIfSyntaxParser());

MOZ_ALWAYS_FALSE if you would

@@ +5276,5 @@
>          kid = lexicalDeclaration(YieldIsName, tt == TOK_CONST);
>          if (!kid)
>              return null();
> +        if (!addExportNamesForDeclaration(kid))
> +            return null();

Ah, good catch.

::: js/src/jit-test/tests/modules/duplicate-exports.js
@@ +30,5 @@
> +testSyntaxError("export let x, y, z; export let y;");
> +testSyntaxError("export const v = 0; export const v = 0;");
> +testSyntaxError("export const x = 0, y = 0, z = 0; export const y = 0;");
> +testSyntaxError("export var v; export let v;");
> +testSyntaxError("export var v; export const v = 0;");

Could you add one more case testing |export let v; export const v;|?

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/f6271cdfbdb9

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/f6271cdfbdb9