Intent to ship: :read-only / :read-write pseudo-classes

[Emilio Cobos Álvarez]

*Summary: *Make our :-moz-read-only / :-moz-read-write pseudo-classes
match the spec, and un-prefix them.

*Bug: *Bug 312971 <https://bugzil.la/312971>

*Standard: *https://html.spec.whatwg.org/#selector-read-only
<https://html.spec.whatwg.org/#selector-read-only>//

*Platform coverage: *All

*Preference: *None. We've shipped the prefixed version of this
pseudo-class since forever.

*DevTools bug: *N/A

*Other browsers:* All other browsers ship it since a long time ago
according to caniuse <https://caniuse.com/#feat=css-read-only-write>.
Safari matches the spec. Chromium deviates from it
<https://bugs.chromium.org/p/chromium/issues/detail?id=255351>.

*web-platform-tests: *There are some rather broken tests and some tests
for dynamic changes. I'm fixing the tests to match the spec as part of
this work.

*Secure contexts: *This will not be restricted to secure contexts, like
many other CSS features. We ship the prefixed pseudo-class to non-secure
contexts, and other browsers ship the unprefixed version to them as well.

*Is this feature enabled by default in sandboxed iframes? *Yes, like
many other CSS features.

 -- Emilio

[Emilio Cobos Álvarez]

A clarification given this came up in chat.mozilla.org:

I'm keeping the support for parsing the old prefixed versions for
backwards compat, aliased to the un-prefixed ones. We can potentially
remove them, but probably at another time, specially given we're trying
to minimize deprecations / breaking changes.

 -- Emilio

On 5/14/20 2:19 AM, Emilio Cobos Álvarez wrote:
>
> *Summary: *Make our :-moz-read-only / :-moz-read-write pseudo-classes
> match the spec, and un-prefix them.
>
> *Bug: *Bug 312971 <https://bugzil.la/312971>
>
> *Standard: *https://html.spec.whatwg.org/#selector-read-only
> <https://html.spec.whatwg.org/#selector-read-only>
>