Fix broken transition toggle, cancellation, and delay

[yezhizhen]

1. Remove unnecessary "mut" specifier for clarity
2. Implement more all CSS transition steps according to spec. Able to cancel more all running transitions as expected, with same test case in the first linked issue
3. This PR

• fixes transition switch to initial value is failed servo#35833
• fixes No delay when transition duration is 0 servo#35982

Following debug message was triggered by following the action in the first issue.

[2025-03-07T07:18:44Z WARN  style::properties::cascade] apply_prioritary_properties decl: transform: translateY(100px) translateZ(0px), priority: CascadePriority { cascade_level: Transitions, layer_order: LayerOrder(65534) }
[2025-03-07T07:18:44Z WARN  style::properties::cascade] apply_prioritary_properties decl: transform: translateY(0px) translateZ(0px), priority: CascadePriority { cascade_level: AuthorNormal { shadow_cascade_order: ShadowCascadeOrder(0) }, layer_order: LayerOrder(65535) }

It was because the transform: translate in after-change style get over-shadowed by already finished transition style, which has highest cascade priority: Transitions.

New passing test:
css/css-logical/animation-004.html: Transitions from physical to logical update when the direction is changed

Added new test:
css-transitions/transition-remove-and-transform-immediate.html

Servo PR: servo/servo#35978
cc @stevennovaryo @xiaochengh @Asun0204

[nicoburns]

This needs to be rebased on top of the latest main

[yezhizhen]

Test re-running
https://github.com/yezhizhen/servo/actions/runs/13869145195/job/38814205426

PR has now been rebased

[yezhizhen]

What should I rebase on now? I got many conflicts when rebasing on main.

[Loirooriol]

I force-pushed the main branch to sync changes from upstream, which is not ideal for PRs.

With your branch at 08279e1, you should be able to do

git rebase --onto main 7ee9643e7ff1633c709f4ffd683050eb3c726ec9 fix-transition-order

Where 7ee9643 is the nearest common ancestor of your branch and https://github.com/servo/stylo/commits/2025-03-11/

[yezhizhen]

Somehow I cannot compile anymore.. I just fetched the latest Servo main branch.

I am on the latest Servo main branch.
Latest Stylo branch, with my five commits.
But I get a lot of

error[E0053]: method `report_error` has an incompatible type for trait
   --> components\script\dom\fontface.rs:180:20
    |
180 |         _location: cssparser::SourceLocation,
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `style::values::SourceLocation`, found `cssparser::SourceLocation`

[nicoburns]

Somehow I cannot compile anymore.. I just fetched the latest Servo main branch.
I am on the latest Servo main branch. Latest Stylo branch, with my five commits.

@yezhizhen You upgraded to the latest Stylo branch a little too quickly! CI is still running on the corresponding Servo PR (servo/servo#35990). Your code should compile again once that merges. Until then you can run against the 2025-03-12 Stylo branch.

[yezhizhen]

Haha thanks Nico! I will get back tomorrow then :)

[yezhizhen]

I still cannot compile locally, with latest pulled repo
I think there is something wrong with current Cargo.toml in Servo for using local stylo.

I made some adjustments to Cargo.toml in Servo. It starts to compile, but has following errors now:

error[E0277]: the trait bound `ElementState: MallocSizeOf` is not satisfied
   --> D:\Rust\Cargo\git\checkouts\stylo-482338307e42a9ea\6aa5733\style\servo\selector_parser.rs:778:26
    |
778 | #[derive(Debug, Default, MallocSizeOf)]
    |                          ^^^^^^^^^^^^ the trait `MallocSizeOf` is not implemented for `ElementState`

EDIT: Seems to work now after servo/servo#36011

[yezhizhen]

https://github.com/yezhizhen/servo/actions/runs/13914368346/job/38936024866

Regression: Failing WPT test after optimization "Revamp".. Fixing it..

EDIT: Fixed

[yezhizhen]

Passing locally already.

./mach test-wpt _mozilla/css/transitionend_event.html _mozilla/css/transition_calc_implicit.html

Running WPT tests with D:\servo\target\debug\servo.exe
Running 2 tests in web-platform-tests

Ran 2 tests finished in 5.8 seconds.
  • 2 ran as expected.

Running Git actions now.

https://github.com/yezhizhen/servo/actions/runs/13919914249

EDIT: Passed

[yezhizhen]

I just added a new wpt-test in servo/servo#35978, which Servo was failing before this PR.

But the Servo PR has no reviewers yet.