List Block: fix merging with indented list items

[ellatrix]

Description

Fixes #17843. The problem is that create is missing the multilineWrapperTags argument when using it with an (indented) list. This needs to be provided in the attribute definition. Since lists are kind of a strange case, I've added the key as unstable. Ideally, in the future, we use blocks for each list item.

How has this been tested?

See #17843 and the e2e test case I've added.

Screenshots

Types of changes

Bug fix.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[mcsf]

Thanks!

This fixes it for me when using Backspace from the second List, but not when using Delete from the first one. At least on Safari, macOS.

[ellatrix]

@mcsf Oops, forgot that there are two create calls, for each block. Should be fixed now.

[ellatrix]

Introduced in #14640, which I don't think was included in WP 5.2.

[mcsf]

Thanks for the quick fix! Works well for me.

Where do you see __unstableMultilineWrapperTags going in the future? Do we need a follow-up issue to revise? I ask only because it's introducing a hidden interface, but as far as the fix goes it looks good to merge.

[ellatrix]

@mcsf I see it as something special that is only needed for nested lists and shouldn't be needed for other blocks. In addition, I think we'd like to revise the list block in the future to use nested block and one rich text instance per item.

Since lists are kind of a strange case, I've added the key as unstable. Ideally, in the future, we use blocks for each list item.

[ellatrix]

Thanks for the review!

[ellatrix]

To be honest, I wish we had done the same for multiline, but it's been around for a long time... It you think it's better to remove the __unstable prefix, I'm fine with that.

[mcsf]

To be honest, I wish we had done the same for multiline, but it's been around for a long time... It you think it's better to remove the __unstable prefix, I'm fine with that.

No, I think it's better to keep the prefix!