[cssom] [css-cascade] Legacy shorthands never appearing on cssText has unfortunate effects when variable references are involved.

[emilio]

https://drafts.csswg.org/css-cascade-4/#legacy-shorthand means that for:

<div style="page-break-after: var(--a)"></div>

The following happens:

div.style.cssText == "break-after:;"

It's a bit unfortunate, but maybe it's ok, given this is a more general issue (#2515), and these shorthands are supposed to be legacy anyway. We could fix legacy shorthands by special-casing them and saying that they serialize in this case, but that's not necessarily great, and certainly propagates the weirdness a bit more in the implementation.

[upsuper]

It's probably more a duplicate of #2515 since they are both about shorthand serialization. But legacy shorthand might be easier to resolve than #2515 if we want to special-case it... It just doesn't seem to be worth it as you said.

[tabatkins]

This does indeed appear to just be a duplicate of #2515, so we'll go ahead and close this one.