Shadow: enable shadow for more blocks

[madhusudhand]

What problem does this address?

As of Gutenberg 17.3, only a button block supports shadow feature. Add support to more blocks.

What is your proposed solution?

Enable the shadow support to following blocks.

• Button — ready for review in Add effects/box shadow tools to block inspector #57654
• Cover
• Image
• Group
• Column and Columns

Enable for more blocks based on the feedback.

[annezazu]

With Column, Columns, and Image support added, I'm going to assume this can be removed from 6.5 with GB 17.7RC1 shipped today. Happy to add back if needed though.

[colinduwe]

Here's a PR to add shadow support to the Post Featured Image Block
#59616

[markhowellsmead]

Was there an explicit decision made to exclude the group block this time around? It would seem to be one of the most logical container blocks to include in the first launch. It would be good to understand and communicate the reasoning by only including particular blocks when adding features which make sense globally.

[annezazu]

Yes! There was an explicit decision made as you can see in this PR: #57982 TLDR: more testing is needed.

[markhowellsmead]

Thanks for the reply, Anne. I can see that testing is needed from that but it’s unclear what issues require more extensive testing than any of the other blocks which now have support. Is the implementation of the control to the group block more complicated than on other containers? Is there any testing I can do which would help?

[vcanales]

Is the implementation of the control to the group block more complicated than on other containers?

This is more or less it. The group and cover block would require changes in the block markup, such as additional wrappers, to make sure that the shadow is rendered correctly and in accordance with the blocks border style. It's not necessarily more complicated, but additional markup wrappers have the potential to introduce regressions down the line.

[markhowellsmead]

Thanks for the explanation. Is the necessity because of multiple box shadows? How is that different from a column block?