Web-Facing Change PSA: Expose CSSFontFeaturesValueRule
Chromestatus
Contact emails
rby...@chromium.org, tanna...@gmail.comSpecification
https://drafts.csswg.org/css-fonts/#cssfontfeaturevaluesruleDesign docs
https://developer.mozilla.org/en-US/docs/Web/API/CSSFontFeatureValuesRule
Summary
We were accidentally missing the [Exposed=Window] on the CSSFontFeaturesValueRule interface, so window.CSSFontFeaturesValueRule is incorrectly undefined even though the API was otherwise exposed. This interface has no constructor and it's unlikely that any website would be looking for it specifically, but it's technically potentially helpful for feature detection.
Blink component
Blink>CSSTAG review
NoneTAG review status
Not applicableRisks
Interoperability and Compatibility
No behavior change other than 'CSSFontFeatureValuesRule in window'. Like all new APIs exposed on 'window' there is a little risk that a poorly written website could be impacted, eg. if a website was relying on legacy features like window.CSSFontFeatureValuesRule mapping to an <iframe name=CSSFontFeatureValuesRule>. However in this case I judge the risk to be virtually non-existent because: 1) This is a long, specific and obscure name - extremely unlikely to be used accidentally by a website (as window.Report was). 2) Firefox and Safari have already shipped this API without issue 3) I searched all of GitHub for 'CSSFontFeatureValuesRule' and didn't get a single hit - very unusual.
Gecko: Shipped/Shipping (https://developer.mozilla.org/en-US/docs/Web/API/CSSFontFeatureValuesRule)
WebKit: Shipped/Shipping
Web developers: No signals (https://developer.mozilla.org/en-US/docs/Web/API/CSSFontFeatureValuesRule)
Other signals:
WebView application risks
Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?
None
Debuggability
None
Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?
YesIs this feature fully tested by web-platform-tests?
YesFlag name on about://flags
Finch feature name
ExposeCSSFontFeatureValuesRuleRequires code in //chrome?
FalseTracking bug
https://issues.chromium.org/issues/385925149Estimated milestones
No milestones specified
Anticipated spec changes
Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).
NoneLink to entry on the Chrome Platform Status
https://chromestatus.com/feature/6275972238934016?gate=5199584181354496
Rick Byers
Contact emails
rby...@chromium.org, tanna...@gmail.comSpecification
https://drafts.csswg.org/css-fonts/#cssfontfeaturevaluesruleDesign docs
https://developer.mozilla.org/en-US/docs/Web/API/CSSFontFeatureValuesRuleSummary
We were accidentally missing the [Exposed=Window] on the CSSFontFeaturesValueRule interface, so window.CSSFontFeaturesValueRule is incorrectly undefined even though the API was otherwise exposed. This interface has no constructor and it's unlikely that any website would be looking for it specifically, but it's technically potentially helpful for feature detection.
Blink component
Blink>CSSTAG review
NoneTAG review status
Not applicableRisks
Interoperability and Compatibility
No behavior change other than 'CSSFontFeatureValuesRule in window'. Like all new APIs exposed on 'window' there is a little risk that a poorly written website could be impacted, eg. if a website was relying on legacy features like window.CSSFontFeatureValuesRule mapping to an <iframe name=CSSFontFeatureValuesRule>. However in this case I judge the risk to be virtually non-existent because: 1) This is a long, specific and obscure name - extremely unlikely to be used accidentally by a website (as window.Report was). 2) Firefox and Safari have already shipped this API without issue 3) I searched all of GitHub for 'CSSFontFeatureValuesRule' and didn't get a single hit - very unusual.