Fix PHP 8.4 deprecation warnings with null parameter handling

[obenland]

Proposed changes:

• Fixed PHP 8.4 deprecation warnings caused by passing null values to WordPress core functions
• Cast values to string in get_summary() methods for User, Blog, and Application models before passing to wp_kses()
• Added null coalescing operators in Actors collection for get_name() and get_summary() calls to provide empty string fallbacks
• Updated sanitize callback in ActivityPub class to cast input to string before wp_kses() processing
• These changes prevent "Passing null to parameter of type string" deprecation warnings in PHP 8.4

Other information:

• Have you written new tests for your changes, if applicable?

Testing instructions:

• Set up a local WordPress environment with PHP 8.4
• Enable WordPress debugging by adding these lines to wp-config.php:

  define('WP_DEBUG', true);
  define('WP_DEBUG_LOG', true);
  define('WP_DEBUG_DISPLAY', true);

• Install and activate the ActivityPub plugin
• Create or edit a user profile with an empty bio/description field
• Create a blog post and view it in the frontend
• Check for PHP deprecation warnings in the debug log or on screen
• Before this fix: Multiple "Passing null to parameter Catchall-Account #1 ($content) of type string" warnings would appear
• After this fix: No deprecation warnings should appear when handling null values in user descriptions, blog summaries, or ActivityPub content processing

Changelog entry

• Automatically create a changelog entry from the details below.

Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Added - for new features
• Changed - for changes in existing functionality
• Deprecated - for soon-to-be removed features
• Removed - for now removed features
• Fixed - for any bug fixes
• Security - in case of vulnerabilities

Message

Fix PHP 8.4 deprecation warnings by preventing null values from being passed to WordPress core functions

[Copilot]

Pull Request Overview

This PR fixes PHP 8.4 deprecation warnings caused by passing null values to WordPress core functions that expect string parameters. The changes ensure type safety by casting potentially null values to strings before passing them to functions like wp_kses().

Key Changes:

• Added string casting in model classes (User, Blog, Application) to prevent null values from being passed to wp_kses()
• Added null coalescing operators in the Actors collection to provide empty string fallbacks
• Updated sanitize callback in ActivityPub class to cast input to string before processing

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
includes/model/class-user.php	Cast description to string before wp_kses() processing
includes/model/class-blog.php	Cast summary to string and simplified wp_kses() call
includes/model/class-application.php	Cast bloginfo description to string and simplified wp_kses() call
includes/collection/class-actors.php	Added null coalescing operators for get_name() and get_summary() calls
includes/class-activitypub.php	Cast value to string in sanitize callback before wp_kses()
tests/includes/handler/class-test-inbox.php	Added actor field to test data array
tests/includes/handler/class-test-announce.php	Refactored test methods and removed unused properties
.github/changelog/2085-from-description	Added changelog entry for the fix

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