1378858 - rust-cssparser treats quoted URLs as a "url" function followed by a string

Status: NEW

(Core :: CSS Parsing and Computation, defect, P3)

Description

[Josh Matthews [:jdm]]

rust-cssparser is modeled after a more recent change to the CSS parsing specification. It's generally black-box compatible with the previous representation that Gecko's parser follows (a single URL token that indicates whether it's quoted or not), but it does affect the error reporting capabilities of the parser for invalid quoted URLs. test_parser_diagnostics_unprintables.html explicitly checks some cases where Stylo's parsing is unable to report the actual invalid string value the same way that Gecko can.

Comment 1

[Daniel Holbert [:dholbert]]

jdm, could you clarify what the real-world impact of this is?  (Is it only absence/presence of quotes in error reports in the browser console?)

And, should this block shipping 57/stylo?

Comment 2

[Josh Matthews [:jdm]]

The real world impact is that erroneous CSS like `x { url('foo') }` reports slightly less informative error messages under Stylo than Gecko.

Gecko:
Expected declaraction but found `url('foo')`.

Stylo:
Expected declaration but found `url(`.

This should not block shipping.

Comment 3

[Firefox Bug Husbandry Bot]

https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Move_fix-optionals