Posts: Preserve updated slugs when restoring trashed posts

[ArkaPrabhaChowdhury]

Summary

This updates the trashed-post slug flow so WordPress preserves an explicitly updated slug when a post is restored from rash, and keeps _wp_desired_post_slug in sync when the slug changes while the post remains trashed.

Problem

In Trac ticket #44805, changing a post slug while the post was trashed could be lost on restore/publish. There was also a related case where publishing from rash with a new slug in the same update could incorrectly restore the older stored desired slug.

Trac ticket: https://core.trac.wordpress.org/ticket/44805

Changes

• Only restore _wp_desired_post_slug when the slug was not actually changed in the current update.
• When a trashed post's slug is updated while it remains in rash, store that updated desired slug and keep the persisted trashed slug suffixed.
• Add regression tests for:
  • updating the slug while trashed
  • publishing after updating the slug while trashed
  • publishing with a new slug in the same update

Root cause

wp_update_post() merges the existing database row into the update payload, so simply checking whether post_name is set is not enough to determine whether the slug changed in the current request.

Testing

• phpcbf --standard=phpcs.xml.dist src/wp-includes/post.php tests/phpunit/tests/post/wpInsertPost.php
• phpcs --standard=phpcs.xml.dist src/wp-includes/post.php tests/phpunit/tests/post/wpInsertPost.php

ode ./tools/local-env/scripts/docker.js run --rm php ./vendor/bin/phpunit tests/phpunit/tests/post/wpInsertPost.php --filter "test_(updating_a_trashed_posts_slug_should_update_the_stored_desired_post_name|publishing_a_trashed_post_should_keep_an_updated_slug|publishing_a_trashed_post_with_a_new_slug_in_the_same_update_should_keep_the_new_slug)"

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[github-actions]

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