Taxonomy: Allow searching terms containing ampersands and HTML entities

[robelsust]

Taxonomy: Allow searching terms containing ampersands and HTML entities

Trac ticket: https://core.trac.wordpress.org/ticket/66279

---

Description

When term names are saved in WordPress, _wp_specialchars() encodes ampersands as & into wp_terms.name (priority 30 on pre_term_name in default-filters.php).

Prior to this change, WP_Term_Query::get_search_sql() created search clauses using only the raw $search value:

((t.name LIKE '%search%') OR (t.slug LIKE '%search%'))

Because MySQL does not equate raw '&' with '&', searching for terms containing ampersands (such as "Tour & ", "Tour & Travel", or "& Travel") failed completely on both wp-admin/edit-tags.php and any queries powered by WP_Term_Query / get_terms( array( 'search' => ... ) ).

Solution

In WP_Term_Query::get_search_sql():

1. Check if the search term contains characters requiring HTML entity encoding (_wp_specialchars( $search, ENT_COMPAT, 'UTF-8', true )).
2. Decode pre-encoded entities (wp_specialchars_decode()) to support searches submitted with entities.
3. If distinct variants are found, expand the search query with an OR condition across both forms:

   (((t.name LIKE '%Tour & %') OR (t.slug LIKE '%Tour & %')) OR ((t.name LIKE '%Tour & %') OR (t.slug LIKE '%Tour & %')))

4. If no special characters are detected, a single clause is generated, preserving identical execution and indexing performance for standard terms.

Testing Instructions

1. Create a category named Tour & Travel.
2. Search for Tour & (with a trailing space) on Posts -> Categories (wp-admin/edit-tags.php?taxonomy=category).
3. Verify that Tour & Travel is found in the search results table.
4. Run PHPUnit test suite:

   vendor/bin/phpunit tests/phpunit/tests/term/getSearchSql.php
   vendor/bin/phpunit -c tests/phpunit/multisite.xml tests/phpunit/tests/term/getSearchSql.php

5. Run PHPCS:

   vendor/bin/phpcs src/wp-includes/class-wp-term-query.php tests/phpunit/tests/term/getSearchSql.php

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props therssoftware.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[github-actions]

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
• A fresh instance is created each time the link below is clicked.
• Every time this pull request is updated, a new ZIP file containing all changes is created. If changes are not reflected in the Playground instance,
  it's possible that the most recent build failed, or has not completed. Check the list of workflow runs to be sure.

For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.