1926969 - Reject `light-dark()` in `@property` as not computationally independent.

Status: ASSIGNED

(Core :: CSS Parsing and Computation, defect)

Description

[David Shin[:dshin] (PTO Til 24th)]

Attachment: Minimum Reproducible Case

As mentioned in bug 1924562 comment 2, light-dark is not computationally independent, which means the declaration should be dropped. But it seems like we just resolve to red.

As observed with the test case in console with CSS warnings/errors enabled, specifying 1em for a <length> property causes the declaration to be dropped, but the first one does not.

Comment 1

[Zach Hoffman [:zrhoffman]]

Attachment: Bug 1926969 - Rename allows_font_relative_lengths to allows_computational_dependence r=#style

Bug 1926969 introduces a new example of computational dependence: The
light-dark() function. So specific references to lengths, like
allows_font_relative_lengths, should be generalized.

This patch also renames ParsingMode::DISALLOW_FONT_RELATIVE to
ParsingMode::DISALLOW_COMPUTATIONALLY_DEPENDENT`.

Comment 2

[Zach Hoffman [:zrhoffman]]

Attachment: Bug 1926969 - Mark color-scheme depent colors as computationally dependent. r=tlouw,#style

Because light-dark() dependens on color-scheme, it is not
computationally independent.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9377aa9a7a6f
Rename allows_font_relative_lengths to allows_computational_dependence r=firefox-style-system-reviewers,emilio

Comment 4

[Tom S. (please needinfo tschuster)]

Do the devtools show something useful when the declaration is dropped?

Comment 5

[Zach Hoffman [:zrhoffman]]

Once bug 1916584 is resolved, DevTools will say:

@property initial-value descriptor ‘light-dark(red, green)’ is not computationally independent.

Comment 6

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/9377aa9a7a6f

Comment 7

[BugBot [:suhaib / :marco/ :calixte]]

The leave-open keyword is there and there is no activity for 6 months.
:emilio, maybe it's time to close this bug?
For more information, please visit BugBot documentation.

Comment 8

[Zach Hoffman [:zrhoffman]]

Before landing the patch, I want to open a spec issue to document this interpretation of the spec.

Comment 9

[James Graham [:jgraham]]

Did we file the spec issue here? It seems like we're in a situation where all browsers agree on a specific behaviour, so the longer we wait the higher the chance of getting a compat issue if we try to change anything.

Comment 10

[Zach Hoffman [:zrhoffman]]

(In reply to James Graham [:jgraham] from comment #9)

Did we file the spec issue here? It seems like we're in a situation where all browsers agree on a specific behaviour, so the longer we wait the higher the chance of getting a compat issue if we try to change anything.

Sorry for the delay, I have filed the spec issue. https://github.com/w3c/csswg-drafts/issues/12735