get_block_wrapper_attributes: id and aria-label should not be merged

[wildworks]

Originally reported in ​https://github.com/WordPress/gutenberg/issues/75251

props to @mamaduka, @adrock42.

If a dynamic block supports id or aria-label, those attributes are automatically injected into the block via the get_block_wrapper_attributes function. However, if the user explicitly passes them, they are merged, resulting in a space between them. This is not the correct format, especially for id.

Perhaps the id and aria-label attributes should respect explicit user-added values ​​instead of being merged.

In particular, the anchor support (id) added to all dynamic blocks in the 6.9 release may affect many consumers, so let's fix that in the 7.0 release.

Trac ticket: https://core.trac.wordpress.org/ticket/64603

Trac ticket: https://core.trac.wordpress.org/ticket/64603

Oh, I re-forked the wordpress-develop repo and it seems all my submitted open PRs were closed 😂 I submitted a new PR that is equivalent to this one. ​https://github.com/WordPress/wordpress-develop/pull/10922

Sorry for the late reply.

After some consideration, I decided to refactor the get_block_wrapper_attributes() function overall to make it more robust and secure.

• Define ​callback functions that define how to merge or override each attribute.
• Sanitize style and class attribute values
• More flexibly handle redundant semicolons in style attributes
• Added a unit test to directly assert the return value of get_block_wrapper_attributes().

[r1k0]

Patch Testing Report

Patch Tested: ​https://github.com/WordPress/wordpress-develop/pull/10922

Environment

• WordPress: 7.0-beta4-61919-src
• PHP: 8.3.30
• Server: nginx/1.29.5
• Database: mysqli (Server: 8.4.8 / Client: mysqlnd 8.3.30)
• Browser: Chrome 145.0.0.0
• OS: Windows 10/11
• Theme: Twenty Twenty-Five 1.4
• MU Plugins: None activated
• Plugins:
  • Block Development Examples - Block Dynamic Rendering 64756b 0.1.0
  • Test Reports 1.2.1

Steps taken

1. Download this dynamic block plugin ​https://github.com/WordPress/block-development-examples/releases/download/latest/block-dynamic-rendering-64756b.zip from ​WordPress block-development-examples.
2. Upload the plugin and activate it.
3. Head over to the plugin files, and add this code to the build/block.json under the "example": {},

     "attributes": {
             "anchor": {
                     "type": "string"
             }
     },
   

4. In the same file, add "anchor": true inside the support object then save the file.
5. Edit the build/render.php file and add this code just above the <p> tag

   <?php
   $block_wrapper_attributes = get_block_wrapper_attributes( [
           'id'         => $attributes[ 'anchor' ],
   ] );
   
   ?>
   

6. In the same file, remove get_block_wrapper_attributes() in the <p> tag and add $block_wrapper_attributes. In the end it should look like this, then save the file.

   <p <?php echo wp_kses_data( $block_wrapper_attributes  ); ?>>
           <?php esc_html_e( 'Block with Dynamic Rendering – hello!!!', 'block-development-examples' ); ?>
   </p>
   

7. Head over to your dashboard, and add a new post.
8. In the editor, add the Block Dynamic Rendering block.
9. Add my-anchor in HTML anchor input field, save the post and view the post in the frontend.
10. Inspect the paragraph added by the block.
11. ✅ Patch is solving the problem

Expected result

• The id attribute now holds one value and not two (an original and a duplicate).

Additional Notes

• I wasn't able to get merged values when it came to aria-label.

Screenshots/Screencast with results

Before:

After:

[audrasjb]

From @wildworks:

Strictly speaking, this isn't a new bug introduced in 7.0. However, the issue became prominent because dynamic blocks newly supported anchors in 7.0.

Therefore, I'm adding trunk version so we can continue to iterate on this ticket during RC.

@westonruter Thanks for the review!

[wildworks]

In 62068:

Blocks: Fix wrapper attribute merging in get_block_wrapper_attributes().

Replace the previous generic concatenation logic in get_block_wrapper_attributes() with attribute-specific merge behavior:

• Add explicit merge callbacks for each attribute.
• Merge style values safely, normalize trailing semicolons, and sanitize the result.
• Merge class values with deduplication .
• Treat id and aria-label as override attributes, giving precedence to explicitly passed extra attributes.

Props adrock42, mamaduka, r1k0, westonruter, wildworks.

Fixes #64603.