Using new wp_register_block_types_from_metadata_collection in PHP 8.2 produces warning

[Lovor01]

Description

When registering blocks with wp_register_block_types_from_metadata_collection and WP_DEBUG is set to true, a following warning is produced:

PHP Deprecated: dirname(): Passing null to parameter #1 ($path) of type string is deprecated ...

Step-by-step reproduction instructions

Set PHP to 8.2 version (probably the same with above versions)
Change multiple block registration to above function
Set 'WP_DEBUG to true in wp-config.php

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure

[t-hamano]

Thanks for the report, but I can't reproduce the problem.

My test steps are as follows:

• Scaffold a WordPress plugin that registers a block with the wp-env enabled: npx @wordpress/create-block my-block --wp-env
• open the my-block directory in my code editor
• Scafford a second block into the src directory: cd ./src && npx @wordpress/create-block my-block-sub --no-plugin && cd ../
• Build the source: npm run build
• Update wp-env to update the config and php version:

  {
  	"$schema": "https://schemas.wp.org/trunk/wp-env.json",
  	"plugins": [ "." ],
  	"core": "WordPress/WordPress",
  	"phpVersion": "8.2",
  	"env": {
  		"tests": {
  			"config": {
  				"WP_DEBUG": true,
  				"SCRIPT_DEBUG": true
  			}
  		}
  	}
  }

• Launch the local environment: npm run env start
• Confirm that I can insert my two custom blocks
• There is no PHP warning.

---

@Lovor01 could you tell us your environment?

• What is your WordPress version? It should be 6.8. or 6.8.1.
• What is the OS, Windows OS or Mac OS?
• Could you provide a full PHP warning message?

[Lovor01]

WP 6.8.1
Windows 11

[05-Jun-2025 11:03:57 UTC] PHP Deprecated:  dirname(): Passing null to parameter #1 ($path) of type string is deprecated in C:\example\public\wp-includes\blocks.php on line 223
[05-Jun-2025 11:03:57 UTC] PHP Stack trace:
[05-Jun-2025 11:03:57 UTC] PHP   1. {main}() C:\example\public\wp-admin\post.php:0
[05-Jun-2025 11:03:57 UTC] PHP   2. require_once() C:\example\public\wp-admin\post.php:12
[05-Jun-2025 11:03:57 UTC] PHP   3. require_once() C:\example\public\wp-admin\admin.php:35
[05-Jun-2025 11:03:57 UTC] PHP   4. require_once() C:\example\public\wp-load.php:50
[05-Jun-2025 11:03:57 UTC] PHP   5. require_once() C:\example\public\wp-config.php:94
[05-Jun-2025 11:03:57 UTC] PHP   6. do_action($hook_name = 'init') C:\example\public\wp-settings.php:727
[05-Jun-2025 11:03:57 UTC] PHP   7. WP_Hook->do_action($args = [0 => '']) C:\example\public\wp-includes\plugin.php:517
[05-Jun-2025 11:03:57 UTC] PHP   8. WP_Hook->apply_filters($value = '', $args = [0 => '']) C:\example\public\wp-includes\class-wp-hook.php:348
[05-Jun-2025 11:03:57 UTC] PHP   9. makeiteasy_altius_blocks_block_init_JSON('') C:\example\public\wp-includes\class-wp-hook.php:324
[05-Jun-2025 11:03:57 UTC] PHP  10. wp_register_block_types_from_metadata_collection($path = 'C:\\example\\wp-content\\plugins\\altius-blocks/build', $manifest = 'C:\\example\\wp-content\\plugins\\altius-blocks/build/blocks-manifest.php') C:\example\public\wp-content\plugins\altius-blocks\altius-blocks.php:62
[05-Jun-2025 11:03:57 UTC] PHP  11. register_block_type_from_metadata($file_or_folder = 'C:/example/public/wp-content/plugins/altius-blocks/build/cards-inner/block.json', $args = *uninitialized*) C:\example\public\wp-includes\blocks.php:400
[05-Jun-2025 11:03:57 UTC] PHP  12. register_block_script_handle($metadata = ['$schema' => 'https://schemas.wp.org/trunk/block.json', 'apiVersion' => 2, 'name' => 'makeiteasy/cards-vertical-inner', 'title' => 'Stavka', 'description' => 'Stavka za blok istaknute kategorije', 'category' => 'altius', 'version' => '1.0.0', 'icon' => 'star', 'textdomain' => 'altius', 'editorScript' => 'file:./index.js', 'supports' => [], 'parent' => [0 => 'makeiteasy/cards-vertical'], 'attributes' => ['inclination' => [...]], 'file' => NULL], $field_name = 'editorScript', $index = *uninitialized*) C:\example\public\wp-includes\blocks.php:611
[05-Jun-2025 11:03:57 UTC] PHP  13. dirname($path = NULL) C:\example\public\wp-includes\blocks.php:223

[t-hamano]

@Lovor01 Thanks for the info.

Looking at your log, the error should happen here:

https://github.com/t-hamano/wordpress-develop/blob/33a612053d5db243ac928a99ccec41d6e2f8a80e/src/wp-includes/blocks.php#L223

This means that the path to block.json is not referenced correctly. How are you using the wp_register_block_types_from_metadata_collection function?

[Lovor01]

function makeiteasy_altius_blocks_block_init_JSON() {

	/**
	 * @disregard P1010
	 */
	wp_register_block_types_from_metadata_collection(
		__DIR__ . '/build',
		__DIR__ . '/build/blocks-manifest.php'
  );
}
add_action( 'init', 'makeiteasy_altius_blocks_block_init_JSON' );

This is in a plugin file.

[t-hamano]

@Lovor01 can you provide a whole plugin file via a zip file or a GitHub link? It's probably not caused by the OS, but I'm not sure yet if it's a problem with the wp_register_block_types_from_metadata_collection function itself.

[Lovor01]

I think I have a clue what can cause this - I have a nested blocks in file structure.
For example, if cards-inner block is inner block of cards-vertical, it is also placed inside cards-vertical block and compiled correctly. However, new type of block registration does not support nested structures.

[Lovor01]

See this image from build directory

[Lovor01]

I flattened my file structure and error disappeared, I can confirm this was the cause. However, since compilation with nested block file structure works fine and it is very convenient to use with many blocks in single plugin, I propose to enhance this block registration to also work with nested block structures. I will open a separate issue for that.

[jkrrv]

@Lovor01 Did you open a separate issue for this? I'm wanting to track progress on resolution here, and I'm not seeing a corresponding issue.

[Lovor01]

I will open it now.

[Lovor01]

@jkrrv see #71036