Closed Bug 1389187 Opened 7 years ago Closed 6 years ago

stylo: Stylo web-platform-test regressions compared to Gecko


(Core :: CSS Parsing and Computation, enhancement, P5)




Tracking Status
firefox-esr52 --- unaffected
firefox55 --- wontfix
firefox56 --- wontfix
firefox57 --- affected


(Reporter: cpeterson, Unassigned)


(Depends on 1 open bug)


(Keywords: meta)

James Graham reports the following web-platform-test differences between Stylo and Gecko. Since Stylo now passes some web-platform-test cases that Gecko fails, we should make sure we're not unintentionally shipping new CSS features in Stylo (bug 1337166).

The following test cases PASS with Gecko but FAIL or TIMEOUT with Stylo:


The following test cases PASS with Stylo but FAIL with Gecko:

Depends on: 1390339
@font-feature-values rule support should fix the css-fonts-3 failures.
Depends on: 1355721
I believe the transform-rounding-001.html failure has the same underlying issue as floating-point rounding issue.
Depends on: 1370779
The 3 (out of 4) wpt related to @import can be fixed trivially:

To fix /css/CSS2/cascade/at-import-009.xht, we need the same mechanism as bug 1388911.
Depends on: 1388911
Oh, hmmm, it doesn't really.

So the test coverage actually isn't good enough :)
No longer depends on: 1388911
Servo PR for the four @import-related tests:
Oh, I thought the @import-related tests are trivial to fix... actually they are not... Fixing them is much more involving...

I've probably met the hardest lifetime problem I've ever tried to deal :(
(In reply to Xidorn Quan [:xidorn] UTC+10 from comment #2)
> I believe the transform-rounding-001.html failure has the same underlying
> issue as floating-point rounding issue.

No. I was misled by the name. There is nothing about the serialization in this test at all.
No longer depends on: 1370779
Depends on: 1392161
Depends on: 1392170
No longer depends on: 1392170
For /css/css-writing-modes-3/text-orientation-script-001.html, w3c/web-platform-tests#6949 should make it much faster, and not timeout for stylo anymore, but we may still want to know why Stylo is so much slower than Gecko on this case. We can do that in bug 1392170.
* font-variant-alternates-related tests are bug 1355721
* transform-rounding-001.html is bug 1392161
* text-orientation-script-001.html is w3c/web-platform-tests#6949 and bug 1392170
* @import-related tests have been fixed

I'm not too concerned about test that stylo passes while gecko fails. We may want to file bugs for some of them against bug 1365771, though.

I don't think there is any code work in this bug. It should basically just a meta, so downgrade to P5.
Keywords: meta
Priority: P2 → P5
I found that there are some stylo-specific issues remaining in shape-outside tests. IIRC they are related to in unit. We may need to investigate what happens there.
Depends on: 1396692
All the dependencies are fixed?
There are still some stylo-specific failures:

Known ones:
* 2dcontext/text-styles/2d.text.font.parse.system.html: this is because of bug 1374885, where Gecko's behavior (returning empty) is definitely undesired, but happens to satisfy this test.
* css/css-align-3/content-distribution/place-content-shorthand-00{2,4,6}.html: this is bug 1363971 where we need to update the impl to match the new spec.
* css/css-fonts-3/test_font_feature_values_parsing.html: seems to be some parsing / serialization disagreement.

Need investigation:
* css/css-variables-1/variable-animation-substitute-within-keyframe*.html
* css/css-variables-1/variable-substitution-variable-declaration.html
* cssom/getComputedStyle-pseudo.html

Shadow DOM bug 1293844 related failures:
* dom/interfaces.html
* html/semantics/forms/the-label-element/label-attributes.html
* intersection-observer/shadow-content.html
* shadow-dom/*
Depends on: 1402212
Depends on: 1402217
Depends on: 1402219
I don't think there's any point in keeping this open.
Closed: 6 years ago
Resolution: --- → WORKSFORME
You need to log in before you can comment on or make changes to this bug.