[css-transforms-1] The computed value of `transform` if the transformed element is display:none

[BorisChiou]

Just curious about where we define the computed value of transform property for display:none element (or in the display:none subtree).

Per this WPT PR#36380, it expects the computed value of transform property is always none if we set this element display:none (or in the display:none subtree). However, I cannot find the specific words in the spec (e.g. css-transforms-1 and css-display-3) to mention this behavior.

Should we add this into the spec to specify this behavior because it seems this is only for transform property? How about translate/rotate/scale properties? Should they be consistent?

[Loirooriol]

The test is actually checking the resolved value. For properties that have a special resolved value, it tends to be the computed value when in display: none. Making the computed value become none in display: none seems strange to me.

[BorisChiou]

Oh right. Per spec, transform property serializes as the resolved value. However, its result still depends on its computed value, so per the spec, in both css-transforms-1 and css-transforms-2, it's also strange to me to show none in the wpt.

Note: I'd like to update it in Gecko's bug, https://bugzilla.mozilla.org/show_bug.cgi?id=1841292, to accept both cases for now.

[nt1m]

WebKit originally changed to stop returning none when the display value was none in WebKit/WebKit@ae44d0c , but that part was reverted in WebKit/WebKit@3a3a97e due to breaking a site (although that site can probably be fixed on our end, I would be cautious about potential web compat impact here).