[css-typed-om] Semantics of CSSURLImageValue constructor?

[asajeffrey]

https://drafts.css-houdini.org/css-typed-om-1/#cssurlimagevalue says that CSSURLImageValue has a constructor, but not what its semantics should be. In particular, should it throw an exception if called with a string which does not parse as a URL?

[nainar]

Given a string that does not parse as a URL the CSSURLImageValue constructor should throw a TypeError.

[css-meeting-bot]

The CSS Working Group just discussed https://github.com/w3c/css-houdini-drafts/issues/424, and agreed to the following resolutions:

• RESOLVED: CSSURLImageValue that fails to parse as a URL should throw an error

The full IRC log of that discussion

<nainar> Topic: https://github.com//issues/424
<dbaron> Github: https://github.com//issues/424
<fantasai> topic is Semantics of CSSURLImageValue constructor
<fantasai> TabAtkins: Things that construct values based on URLs
<fantasai> TabAtkins: Should we do some early parsing of URL and throw an exception if it fails URL parsing?
<fantasai> TabAtkins: Our opinion is yes
<fantasai> iank_: If you construct a CSSURLImageValue in a PaintWorklet, and invalid, can't use it. what should semantics be?
<fantasai> TabAtkins: Constructed parsers are used in worklets
<fantasai> TabAtkins: Impls doe somehting about this in ServiceWorkers
<fantasai> TabAtkins: Shouldn't be difficult to throw if URL is bad
<fantasai> plinss: This is never synchronouse?
<fantasai> TabAtkins: No resolution
<fantasai> s/synch/async/
<fantasai> Rossen: Any opinions?
<dbaron> I don't really know the current rules for Gecko's URL parser, fwiw.
<fantasai> RESOLVED: CSSURLImageValue that fails to parse as a URL should throw an error
<fantasai> undecided which error?
<fantasai> plinss: Should have a platform-wide error for URL parsing error
<fantasai> iank_: Platform is very inconsistent, some throw TypeError, others throw SyntaxError
<fantasai> dbaron: Sure ServiceWorker relies on this?
<fantasai> iank_ cites stuff