Bug 156530 – :in-range & :out-of-range CSS pseudo-classes shouldn't match disabled or readonly inputs

• Component: CSS
• Status: RESOLVED FIXED

[Chris Rebert]

Created attachment 276300 [details]
Testcase demonstrating the bug

Steps to reproduce the problem:
1. Open the attached testcase webpage in WebKit Nightly.
2. Observe the colors of the outlines of the <input>s.

What is the expected behavior?
The outlines should be green, indicating that the disabled or readonly <input type=number>s did not match the :in-range or :out-of-range CSS pseudo-classes.

What went wrong?
The outlines are orange and red, indicating that the disabled or readonly <input type=number>s matched the :in-range or :out-of-range CSS pseudo-classes.

----

Based on my reading of the HTML spec, :in-range and :out-of-range should never apply to disabled or readonly <input>s.

Per https://html.spec.whatwg.org/multipage/scripting.html#selector-in-range
> The :in-range pseudo-class must match all elements that are **candidates for constraint validation**, have range limitations, and [...]
> The :out-of-range pseudo-class must match all elements that are **candidates for constraint validation**, have range limitations, and  [...]

Per https://html.spec.whatwg.org/multipage/forms.html#candidate-for-constraint-validation
> A submittable element is a **candidate for constraint validation** except when a condition has **barred the element from constraint validation**.

Per https://html.spec.whatwg.org/multipage/forms.html#the-readonly-attribute:barred-from-constraint-validation
> If the **readonly** attribute is specified on an input element, the element is **barred from constraint validation**.

Per https://html.spec.whatwg.org/multipage/forms.html#enabling-and-disabling-form-controls:-the-disabled-attribute:barred-from-constraint-validation
> If an element is **disabled**, it is **barred from constraint validation**.

Thus, disabled and readonly <input>s are barred from constraint validation, meaning they are not candidates for constraint validation, thus causing them to be disqualified by the 1st of the 3 conditions which are required for an element to match :in-range or :out-of-range.

[Radar WebKit Bug Importer]

<rdar://problem/25698037>

[Chris Rebert]

Now fixed in Chrome: https://codereview.chromium.org/1890633002

[Benjamin Poulain]

Created attachment 281527 [details]
Patch

[Simon Fraser (smfr)]

Comment on attachment 281527 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=281527&action=review

> Source/WebCore/html/BaseDateAndTimeInputType.cpp:98
> +    element().setNeedsStyleRecalc();

Is this necessary if the element has no renderer?

> Source/WebCore/html/NumberInputType.cpp:305
> +        renderer->setNeedsLayoutAndPrefWidthsRecalc();

Is this necessary in addition to the setNeedsStyleRecalc? Why are both required?

[Benjamin Poulain]

(In reply to comment #4)
> Comment on attachment 281527 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=281527&action=review
> 
> > Source/WebCore/html/BaseDateAndTimeInputType.cpp:98
> > +    element().setNeedsStyleRecalc();
> 
> Is this necessary if the element has no renderer?

Definitely!
Style is independent from the render tree. You can handle on an offscreen subtree.

> > Source/WebCore/html/NumberInputType.cpp:305
> > +        renderer->setNeedsLayoutAndPrefWidthsRecalc();
> 
> Is this necessary in addition to the setNeedsStyleRecalc? Why are both
> required?

Yes.

The style recalc does not have to force a relayout. Here you also need the layout for properties independent from the style.

[WebKit Commit Bot]

Comment on attachment 281527 [details]
Patch

Clearing flags on attachment: 281527

Committed r202159: <http://trac.webkit.org/changeset/202159>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.