[wp-trac] [WordPress Trac] #63580: render_block does not render innerblocks when used explicitly

[WordPress Trac]

#63580: render_block does not render innerblocks when used explicitly
--------------------------+------------------------------
 Reporter:  yashjawale    |       Owner:  (none)
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  Awaiting Review
Component:  Editor        |     Version:  trunk
 Severity:  normal        |  Resolution:
 Keywords:  2nd-opinion   |     Focuses:
--------------------------+------------------------------

Comment (by iamadisingh):

 == Reproduction Report
 === Description
 This report validates whether the issue can be reproduced.

 === Environment
 - WordPress: 6.9-alpha-60093-src
 - PHP: 8.2.28
 - Server: nginx/1.27.3
 - Database: mysqli (Server: 8.4.5 / Client: mysqlnd 8.2.28)
 - Browser: Chrome 138.0.0.0
 - OS: macOS
 - Theme: Twenty Twenty-Five 1.2
 - MU Plugins: None activated
 - Plugins:
   * Test Render Block Issue 1.0.0
   * Test Reports 1.2.0

 === Actual Results
 1.  ✅ Error condition occurs (reproduced).

 === Additional Notes
 - When using `render_block()` explicitly with programmatically created
 block structures, nested blocks (`innerBlocks`) are not rendered if the
 parent block lacks an `innerContent` array. This affects container blocks
 like `core/column` and `core/columns` where the parent block should render
 its child blocks even without explicit innerContent markup.
 - Parent blocks with `innerBlocks` should render their child blocks
 regardless of whether innerContent is defined, as the child blocks contain
 valid `innerHTML` and `innerContent` properties.
 - The issue lies in how WordPress's `WP_Block::render()` method processes
 blocks. The fix should be in the `WP_Block::render()` method to ensure
 that `innerBlocks` are processed even when innerContent is empty, while
 maintaining backward compatibility with existing behavior.

 === Supplemental Artifacts
 Plugin code used for reproducing the error
 {{{#!php
 <?php
 /**
  * Plugin Name: Test Render Block Issue
  * Description: A plugin to test rendering of blocks with inner blocks.
  * Version: 1.0.0
  */

 $first_column_blocks = [
     'blockName' => 'core/paragraph',
     'attrs' => [],
     'innerBlocks' => [],
     'innerHTML' => '<p>First Global HTML</p>',
     'innerContent' => [
             '<p>First Global HTML</p>',
     ],
 ];

 $second_column_blocks = [
     'blockName' => 'core/paragraph',
     'attrs' => [],
     'innerBlocks' => [],
     'innerHTML' => '<p>Second Global HTML</p>',
     'innerContent' => [
             '<p>Second Global HTML</p>',
     ],
 ];

 $column_layout_block = [
     'blockName' => 'core/columns',
     'attrs' => [],
     'innerBlocks' => [
             [
                     'blockName' => 'core/group',
                     'attrs' => [],
                     'innerBlocks' => [$first_column_blocks],
                     'innerContent' => [
                             null,
                     ],
             ],
             [
                     'blockName' => 'core/group',
                     'attrs' => [],
                     'innerBlocks' => [$second_column_blocks],
                     'innerContent' => [
                             null,
                     ],
             ],
     ],
     'innerContent' => [ null, null] // Required without this nested blocks
 won't render
 ];

 add_action('template_redirect', function() {
     global $column_layout_block;
     echo apply_filters('the_content', render_block($column_layout_block));
 });
 }}}

 When innerContent is added - https://files.catbox.moe/j1qdyr.png
 Without innerContent - https://files.catbox.moe/mitk2k.png

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/63580#comment:5>
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