1752392 - CSSStyleSheet.replace[Sync]() should not replace CSSStyleSheet.cssRules

Status: RESOLVED FIXED

(Core :: DOM: CSS Object Model, defect, P3)

Description

[Guillaume]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.99 Safari/537.36

Steps to reproduce:

1. Create a new CSSStyleSheet
2. Get a reference of its cssRules
3. Run CSSStyleSheet.replaceSync() (or CSSStyleSheet.replace())
4. Compare the reference of cssRules with CSSStyleSheet.cssRules

Demo: https://codepen.io/creativewave/pen/mdqJerz

Actual results:

CSSStyleSheet.cssRules is replaced by a new object when running CSSStyleSheet.replaceSync() (or CSSStyleSheet.replace()).

Expected results:

CSSStyleSheet.cssRules should be the [SameObject] than before running CSSStyleSheet.replaceSync() (or CSSStyleSheet.replace()), as defined by the CSSOM specification:

  [SameObject] readonly attribute CSSRuleList cssRules;

https://drafts.csswg.org/cssom/#ref-for-dom-cssstylesheet-replace

Chrome keeps the same object.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1752392 - Don't drop CSSStyleSheet.cssRules from CSSStyleSheet.replace/Sync(). r=nordzilla,#style,#layout-reviewers

As per spec this object should always return the same JS object.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/092814d96f1d
Don't drop CSSStyleSheet.cssRules from CSSStyleSheet.replace/Sync(). r=firefox-style-system-reviewers,layout-reviewers,boris

Comment 3

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/33834 for changes under testing/web-platform/tests

Comment 4

[Cristian Tuns]

Backed out for causing mochitest failures in test_parseStyleSheetImport.html

• Backout link
• Push with failures
• Push with failures
• Failure Log1
• Failure Log2
• Failure line: webidl/ecmascript-binding/observable-array-ownkeys.window.html | ObservableArray's ownKeys trap - expected FAIL
• Failure line: layout/inspector/tests/test_parseStyleSheetImport.html | reordering preserved suffixed style sheet - got [object CSSStyleSheet], expected [object CSSStyleSheet]
  log 3: https://treeherder.mozilla.org/logviewer?job_id=376069995&repo=autoland

Comment 5

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR was closed without merging

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/842cc90cd235
Don't drop CSSStyleSheet.cssRules from CSSStyleSheet.replace/Sync(). r=firefox-style-system-reviewers,layout-reviewers,boris

Comment 7

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/842cc90cd235

Comment 8

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot