MU Plugin to block transliteration of WooCommerce attributes and attribute terms.

cyr2lat-attributes-in-woocommerce.php

<?php
/**
 * MU Plugin to block transliteration of WooCommerce attributes and attribute terms.
 *
 * @package cyr-to-lat
 */

/**
 * Class Block_WC_Attr_Cyr2lat.
 */
class Block_WC_Attr_Cyr2lat {

	/**
	 * Block sanitize title in cyr2lat plugin.
	 *
	 * @var bool
	 */
	private $block_cyr2lat_sanitize = false;

	/**
	 * WC_Attr_Cyr2lat constructor.
	 */
	public function __construct() {
		add_action( 'plugins_loaded', [ $this, 'init_hooks' ] );
	}

	/**
	 * Init hooks.
	 */
	public function init_hooks() {
		if ( ! function_exists( 'WC' ) ) {
			return;
		}

		add_filter( 'sanitize_taxonomy_name', [ $this, 'sanitize_taxonomy_name_filter' ], - PHP_INT_MAX, 2 );

		add_filter( 'pre_term_slug', [ $this, 'pre_term_filter' ], - PHP_INT_MAX, 2 );
		add_filter( 'pre_insert_term', [ $this, 'pre_term_filter' ], - PHP_INT_MAX, 2 );

		add_filter( 'ctl_pre_sanitize_title', [ $this, 'ctl_pre_sanitize_title_filter' ], - PHP_INT_MAX, 2 );
	}

	/**
	 * Sanitize taxonomy name.
	 *
	 * @param string $sanitized Sanitized taxonomy name.
	 * @param string $taxonomy  Taxonomy name.
	 *
	 * @return string
	 */
	public function sanitize_taxonomy_name_filter( $sanitized, $taxonomy ) {
		if (
			doing_filter( 'product_page_product_attributes' ) ||
			$this->is_called_from( 'wc_create_attribute' )
		) {
			$this->block_cyr2lat_sanitize = true;

			$sanitized = urldecode( sanitize_title( urldecode( $taxonomy ) ) );
		}

		return $sanitized;
	}

	/**
	 * Filters a term field value before it is sanitized.
	 *
	 * @param mixed  $value    Value of the term field.
	 * @param string $taxonomy Taxonomy slug.
	 *
	 * @return mixed
	 */
	public function pre_term_filter( $value, $taxonomy ) {
		if ( 0 === strpos( $taxonomy, 'pa_' ) ) {
			$this->block_cyr2lat_sanitize = true;
		}

		return $value;
	}

	/**
	 * Filters title before sanitization in cyr2lat.
	 *
	 * @param false|string $pre   Preset to false.
	 * @param string       $title Title.
	 *
	 * @return false|string
	 */
	public function ctl_pre_sanitize_title_filter( $pre, $title ) {
		if ( $this->block_cyr2lat_sanitize ) {
			return $title;
		}

		return $pre;
	}

	/**
	 * Check if the code was called from a specific function.
	 *
	 * @param string $function_name Function name.
	 *
	 * @return bool
	 */
	private function is_called_from( $function_name ) {
		$is_called_from = false;
		// phpcs:disable WordPress.PHP.DevelopmentFunctions.error_log_debug_backtrace
		$backtrace = debug_backtrace( ~DEBUG_BACKTRACE_PROVIDE_OBJECT | DEBUG_BACKTRACE_IGNORE_ARGS );
		// phpcs:enable
		foreach ( $backtrace as $backtrace_entry ) {
			if ( $function_name === $backtrace_entry['function'] ) {
				$is_called_from = true;
				break;
			}
		}

		return $is_called_from;
	}
}

new Block_WC_Attr_Cyr2lat();