PHP Warnings in BeTheme with PHP 8.4

Comments

• Phil

  November 21

  Hi,

  I have passed it on to the dev team, and we will correct that.

  
  

  Best regards

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• gnorimaki

  November 29 edited November 29

  Good morning,

  I wanted to add the following information:

  
  

  I've noticed that, in addition to what I mentioned earlier, I also occasionally see the following logs:

  
  

  [24-Nov-2025 15:02:31 UTC] PHP Deprecated: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in .../wp-includes/kses.php on line 1807

  [24-Nov-2025 15:02:31 UTC] PHP Deprecated: htmlentities(): Passing null to parameter #1 ($string) of type string is deprecated in .../wp-content/themes/betheme/functions/theme-functions.php on line 1936

  
  

  Best regards.
• Phil

  November 29

  Thanks for letting us know.

  I will pass this information as well.

  
  

  Best regards

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• gnorimaki

  December 7

  Hi,

  After updating to WP 6.9, I've received more warnings:

  
  

  
  

  ------------------------------------------------------------

  1) "Array to string conversion" warnings

  ------------------------------------------------------------

  
  

  These warnings appear hundreds of times in the log, always referencing the same file and line:

  
  

  PHP Warning: Array to string conversion 

  .../wp-content/themes/betheme/functions/admin/class-mfn-helper.php:96

  
  

  
  

  ------------------------------------------------------------

  2) Missing CSS includes (This is a blog post for which I have a single post template, but the post itself is a plain blog entry without any custom styles anywhere.)

  ------------------------------------------------------------

  
  

  PHP Warning: include_once(.../wp-content/uploads/betheme/css/post-630.css): Failed to open stream: No such file or directory 

  .../wp-content/themes/betheme/functions/theme-head.php:877

  
  

  PHP Warning: include_once(): Failed opening '/wp-content/uploads/betheme/css/post-630.css' for inclusion 

  .../wp-content/themes/betheme/functions/theme-head.php:877

  
  

  This occurs repeatedly and appears to be tied to dynamically generated CSS files that were never created or were removed.

  
  

  
  

  ------------------------------------------------------------

  3) Deprecated PHP warning triggered indirectly through theme execution

  ------------------------------------------------------------

  
  

  PHP Deprecated: preg_replace(): Passing null to parameter #3 ($subject) is deprecated 

  .../wp-includes/kses.php:2018

  
  

  
  

  
  

  ------------------------------------------------------------

  Environment details

  ------------------------------------------------------------

  
  

  - WordPress: 6.9 

  - PHP: 8.4 

  - BeTheme 28.1.13 

  
  

  
  

  Best regards
• Phil

  December 8

  Thanks for being alert.

  I have informed the dev team about that.

  
  

  Best regards

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• Phil

  December 9

  We have prepared a correction for the first two, but to check the last one, we would need WP and FTP access to do a full debug process, as we are not able to replicate that.

  
  

  Best regards

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• gnorimaki

  December 9

  I understand that you are referring to the issue of "kses.php".

  If so, the truth is that this particular one appears very rarely.

  I don't know if you use this directly or if it is native to WP.

  
  

  If you can tell me in which cases it can be used (related to BeTheme) I can do tests (since as I told you in other tickets I have people developing and it is difficult for me to give you access currently, as I did other times).

  
  

  From what I have been investigating the problem is that as of PHP 8.1+ passing null is no longer allowed.

  This does NOT break the website, but it indicates that some plugin or theme (most likely the BeTheme / BeBuilder builder) is sending null values ​​to the filter that WordPress uses to clean HTML.

  
  

  As kses.php receives data I understand what can happen: 

  1. BeTheme or its builder generates dynamic content 

  2. Some of your filters pass null to functions like wp_kses() 

  3. WordPress tries to sanitize it → reaches kses.php 

  4. preg_replace() receives null → warning appears

  
  

  I assume this notice appears when: 

  • builder blocks are loaded from AJAX 

  • there are empty shortcodes 

  • a dynamic field returns null or false 

  • HTML that is not present in some contexts is processed

  
  

  
  

  I understand that, if this is the reason, one of the solutions would be to validate that the content is a string type:

  
  

  $content = $content ?? '';

  
  

  before calling filters that go through wp_kses().

  
  

  
  

  Just an idea in case it helps.

  
  

  Best regards
• Phil

  December 9 edited December 9

  Yes we relate to wp_kses, but we are not yet sure what is triggering it. It does not have to be a direct call inside the theme or a plugin; it may also be invoked indirectly by another function that contains a wp_kses call. To debug this, you need to add the code below in the kses.php file at line 2018 and then review the logs to identify what is causing the invocation.

  if ( is_null( $content ) ) {
      error_log( 'WP_KSES DEPRECATION TRACER: Found NULL subject. Backtrace:' );
      error_log( print_r( wp_debug_backtrace_summary( null, 0, false ), true ) );
  }
  

  

  Best regards

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• gnorimaki

  December 9

  Hi,

  I've implemented debugging in the wp_kses_no_null function and I'll let you know when I see any related results in the log.