[csswg-drafts] [css-lists] [css-pseudo] need to define blockification of outside markers / interaction of display: inline list-item with list-style-position (#6440)

emilio has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-lists] [css-pseudo] need to define blockification of outside markers / interaction of display: inline list-item with list-style-position ==
Outside markers are defined to create block containers. This is as of today implemented in both Gecko and Blink at least as a computed-style-time hack:

 * [Gecko](https://searchfox.org/mozilla-central/rev/5227b2bd674d49c0eba365a709d3fb341534f361/servo/components/style/style_adjuster.rs#258-266).
 * [Blink](https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/css/resolver/style_adjuster.cc;l=292;drc=292a6c3a003c49d93621d39012265e92c62997c5).

Right now that has a visible effect via `getComputedStyle(element, "::marker").display` ([this test](https://github.com/web-platform-tests/wpt/blob/23d801e755183b7b61d7e79c44f20358c1fec957/css/css-pseudo/marker-display-computed.html) tests for it).

However:

 * The spec should probably say how it is implemented given it is observable.
 * That is not quite sound with `display: inline list-item`, because the `display` value may be ignored / overridden.

The last bullet point is, of course, if we agree that `display: inline list-item` ignores `list-style-position` (which Gecko does right now), but it seems a bit under-defined.

So in Gecko, I'm going to change this to be a used-value-time blockification (mostly to prevent the case where we have a block element like `<details>` with `display: inline list-item` and fail to blockify the marker). But I'm happy to adapt to whatever solution we end up with here since we're the only ones implementing `inline list-item` after all.

cc @Loirooriol @MatsPalmgren @jfkthame 

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6440 using your GitHub account


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Received on Monday, 12 July 2021 11:07:34 UTC