Closed Bug 1493748 Opened 7 years ago Closed 7 years ago

[wpt-sync] Sync PR 13193 - [css-properties-values-api] Substitution behavior.

Categories

(Core :: CSS Parsing and Computation, enhancement, P4)

Product:
Core
Component:
CSS Parsing and Computation
Type:
enhancement

Tracking

()

Status:
RESOLVED FIXED
Milestone:
mozilla64
Tracking Flags:
Tracking Status
firefox64 --- fixed

People

(Reporter: wpt-sync, Unassigned)

References

(
URL
)

Details

(Whiteboard: [wptsync downstream])

Sync web-platform-tests PR 13193 into mozilla-central (this bug is closed when the sync is complete). PR: https://github.com/web-platform-tests/wpt/pull/13193 Details from upstream follow. Anders Hartvoll Ruud <andruud@chromium.org> wrote: > [css-properties-values-api] Substitution behavior. > > Currently, registered properties substitute into other values exactly > like specified (like unregistered properties). This means that, for > a \<length>-registered property with a specified value "10em" (for > instance), when that property is substituted via var()-reference, > the tokens "10em" are inserted. This is not correct, and produces the > wrong result with e.g. inherited values. > > This CL changes that, by implementing "absolutization" of registered > custom properties: a process which calculates the computed value of > the property, and then produces a token stream usable for substitution > which is equivalent to the computed value. > > * Currently we resolve var()-references on all custom properties > before applying high-priority properties. This is no longer > possible, because the true value of a custom property (also > unregistered) can not be known until the font has been updated. > Consider: --reg-len: 1em; --unreg:var(--reg-len). Here, the > computed value of --unreg should be "16px" (assuming a font-size > of 16px), and not "1em". If we destructively resolve --unreg > before the font size is known, we end up with the wrong tokens. > > Hence the resolution process has been moved to after the font > has been updated. > > * Custom properties must also be usable from high-priority properties. > Since they are no longer resolved beforehand, they are resolved > "on the fly", non-destructively. "Non-destructively" means that > resolved token streams are not stored on ComputedStyle, such that > any var()-references are kept for the _real_ resolution pass after > the font has been updated. > > This works, because the high-priority properties do not require > proper "absolute substitution" to produce the correct value. > > Note that font-size is special, in that font-relative units may > not be used if they arrive via a registered custom property. > > * There is a special resolving pass for registered custom properties > (ComputeRegisteredVariables). This pass produces non-absolute CSSValues > for calculation of animation. > > * Parsing of registered properties now happens entirely in > CSSVariableResolver, and no longer in variable.cc. Having this in > multiple places is just confusing. > > R=futhark@chromium.org > > Bug: 641877 > Change-Id: Ic705d0808ffcea0ae5db02fb20870767175bb706 > Reviewed-on: https://chromium-review.googlesource.com/1240274 > WPT-Export-Revision: f80e282384e09a9e3c5238207e57bc50d390ffd7
PR 13193 applied with additional changes from upstream: d5d003b4993520826bd7dfb274e355cbba6cb6e8, 689968f390a8c5c897ab5c9fa0f6fe27a40b5cc3
Component: web-platform-tests → CSS Parsing and Computation
Product: Testing → Core
Ran 3 tests and 15 subtests OK : 3 FAIL : 15 New tests that have failures or other problems: /css/css-properties-values-api/registered-properties-inheritance.html Calc expressions are resolved before inheritance: FAIL Explicitly inheriting from a parent with an invalid value results in initial value.: FAIL Explicitly inheriting from a parent with no value results in initial value.: FAIL Font-relative units are absolutized before before inheritance: FAIL Reference to syntax-incompatible variable results in inherited value: FAIL Reference to undefined variable results in inherited value: FAIL /css/css-properties-values-api/var-reference-registered-properties.html Calc expressions are resolved when substituting: FAIL Font-relative units are absolutized when substituting: FAIL Lists with relative units are absolutized when substituting: FAIL
Pushed by wptsync@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/eecc27b7ef23 [wpt PR 13193] - [css-properties-values-api] Substitution behavior., a=testonly
https://hg.mozilla.org/mozilla-central/rev/eecc27b7ef23
Status: NEW → RESOLVED
Closed: 7 years ago
status-firefox64: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla64
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