Make 'inherit' value work correctly for shorthand properties

[liZe]

From Cascading and Inheritance:

If a shorthand is specified as one of the CSS-wide keywords, it sets all of its sub-properties to that keyword […].

It should be probably handled by the expander decorator.

[liZe]

For example, text-decoration: inherit is currently rejected. Some other shorthand properties probably set inherit only for one of the expanded properties.

[Smylers]

For example, text-decoration: inherit is currently rejected.

This is a regression bug, breaking previously correct behaviour.

We've just tried upgrading WeasyPrint from 44 to 51, and discovered we're now getting a warning that we didn't before:

WARNING: Ignored `text-decoration: inherit` at 136:3, invalid value.

and that some links are now getting underlines that they didn't have before the upgrade. Changing inherit to none restores the previous behaviour of no underlines. Presumably text-decoration-line: inherit would work, too.

This regression is particularly unfortunate for the text-decoration property, which didn't even used to be a shorthand: in CSS2, text-decoration took values directly, and MDN says Edge still doesn't support the individual text-decoration-* properties. So there's likely to be a lot of CSS out there setting text-decoration directly, rather than the individual properties.

[liZe]

This regression is particularly unfortunate for the text-decoration property, which didn't even used to be a shorthand

Yes, that’s exactly why this is a regression: text-decoration used to be a simple property in WeasyPrint, but it’s been transformed into a shortand by 9a73fff.

So there's likely to be a lot of CSS out there setting text-decoration directly, rather than the individual properties.

Yes, it’s infortunate. I’ll try to fix this as soon as I can. If anyone is interested, I can also help someone to fix it, the patch should be pretty small and it’s a good way to learn how WeasyPrint works.

[dannyduncan]

Hey @liZe I believe I've come across this issue as well. Any updates on a fix? See my error below when using the sample report.css file from the gh-pages branch.

WARNING: Ignored `text-decoration: inherit` at 153:11, invalid value.

Has anyone already addressed? Happy to help if you can provide some guidance.

[ckepper]

Hey @liZe, I have just submitted this pull request. Please review