Fixes #29691

Problem

Some drafts will render on the published page/post frontend. This happens in two ways:

1. Creating draft pages when searching for things to link to. Like so:

2. Adding a link using the general "link" variation

Why Does This Happen?

In trunk when we link from the general "link" variation this is missing the "type" attribute. Without this information, we can't blindly check to see if an id is a draft. It might actually be a term-id, leading to a bug like: #28712

Proposed changes:

Changes in this PR add the type block attributes to the link consistently regardless of what link variation we use to create the link. This will fix newly added links but not existing links. (The worst case is that we have an old link to a draft that still renders on the front end).

In order to support future custom post types and taxonomies, we should also return the kind (taxonomy|post-type) to make this more clear. Type is not enough information to differentiate if we can check for draft status besides our built-in types (post,page,post_tag,category).

Example custom PortfolioTag Search Result:

Before:

<!-- wp:navigation-link {"label":"PortfolioTag2","id":5,"url":"http://wordpress.local/portfolio_tag/portfoliotag2/"} /-->

After:

<!-- wp:navigation-link {"label":"PortfolioTag2","type":"portfolio_tag","id":5,"url":"http://wordpress.local/portfolio_tag/portfoliotag2/","kind":"taxonomy"} /-->

Testing Instructions w/ WP 5.7

• Install a plugin with custom taxonomies and post types. Create new CPTs and terms.
• Navigate to the post editor
• Add a navigation block
• Add an element using the general link variation
• Search for a (post|page|category|tag)
• Look at code editor

• Verify that in the block editor that the kind and type attributes are present and make sense.

• If it's a draft, verify that the link is visible only in the editor, but not on the published page of the navigation links.

• Verify that links like www.wordpress.org do not contain the id type or kind block attributes.

Testing Instructions w/ WP latest (Custom Link Variations)

• Install a plugin with custom taxonomies and post types. Create new CPTs and terms.
• (Optional) You may also want to edit the plugin to add the new post-labels item_link and item_link_description

• Spin up wordpress-desktop and checkout trunk
• Verify that new link variations appear in inserter:

• Add an element using the general link variation
• Search for a (post|page|category|tag)
• Look at code editor
• Verify that in the block editor that the kind and type attributes are present and make sense.
• Add an element using the custom link variations (post, page, category, your new post type/taxonomy)
• Look at code editor
• Verify that in the block editor that the kind and type attributes are present and make sense.
• Verify that links like www.wordpress.org do not contain the id, type or kind block attributes.

Test Post-Format Links

A post format link looks like http://wordpress.local/type/quote/. This points at the archive of a post type format like quote or image.

To test:

• Install a theme that supports post-formats like Twenty Thirteen

• Create a post using one of the post-format types like "Quote"

• Add a navigation block

• Add a navigation link using the general link variation

• Search for the post-format and individual quote

• Verify that the individual link to a quote has type 'post' and kind 'post-type'.

• Verify that the link to the post-format only has url and label

Behavior when loading links from a menu

• Drafts will render on frontend due to Navigation Editor: Navigation links added to menu only preserve url and label attributes #29793
• Let's fix this in a follow up

TODO:

• Copy any changes from packages/editor/src/components/provider/use-block-editor-settings.js to packages/edit-navigation/src/index.js.
• How to test post-formats?
• Update tests/add new ones
• Test links created in Navigation editor
• Test loading menus