wp_unique_post_slug( string $slug, int $post_id, string $post_status, string $post_type, int $post_parent ): string

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$slugstring

The desired slug (post_name).

$post_idint

Post ID.

$post_statusstring

No uniqueness checks are made if the post is still draft or pending.

$post_typestring

Post type.

$post_parentint

Post parent ID.

Return value

string

Unique slug for the post, based on $post_name (with a -1, -2, etc. suffix)

Performance profile

How much work a call to wp_unique_post_slug() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via ->get_var().

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

8–153

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 270.

Plugin surface

5 hooks

Third-party callbacks on 'pre_wp_unique_post_slug', 'wp_unique_post_slug_is_bad_attachment_slug', 'wp_unique_post_slug_is_bad_hierarchical_slug' run inside this call, and their cost is not bounded by anything here.

Called by

5

5 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly
• querycontent queryget_post()called directly
• optionoption read or writeget_option()called directly
• sqldatabase query->get_var()called directly
• cacheobject cachewp_cache_get()one call below wp_unique_post_slug()
• serializeserialisationmaybe_unserialize()one call below wp_unique_post_slug()

Further down the call graph this can also reach transient. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 11 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_unique_post_slug() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 5

5 hooks fire while wp_unique_post_slug() runs, in this order:

1. 1
   apply_filters( pre_wp_unique_post_slug )filterline 5486 (+22 into the body)

   Filters the post slug before it is generated to be unique.

2. 2
   apply_filters( wp_unique_post_slug_is_bad_attachment_slug )filterline 5513 (+49 into the body)

   Filters whether the post slug would make a bad attachment slug.

3. 3
   apply_filters( wp_unique_post_slug_is_bad_hierarchical_slug )filterline 5549 (+85 into the body)

   Filters whether the post slug would make a bad hierarchical post slug.

4. 4
   apply_filters( wp_unique_post_slug_is_bad_flat_slug )filterline 5605 (+141 into the body)

   Filters whether the post slug would be bad as a flat slug.

5. 5
   apply_filters( wp_unique_post_slug )filterline 5634 (+170 into the body)

   Filters the unique post slug.

Uses · 5

• apply_filters()Calls the callback functions that have been added to a filter hook.
• _truncate_post_slug()Truncates a post slug.
• is_post_type_hierarchical()Determines whether the post type is hierarchical.
• get_post()Retrieves post data given a post ID or post object.
• get_option()Retrieves an option value based on an option name.

Used by · 5

• WP_REST_Posts_Controller::create_item()Creates a single post.
• WP_REST_Posts_Controller::update_item()Updates a single post.
• get_sample_permalink()Returns a sample permalink based on the post name.
• wp_ajax_inline_save()Handles Quick Edit saving a post from a list table via AJAX.
• wp_insert_post()Inserts or update a post.

Source code

View on Trac ↗View on GitHub ↗

5464function wp_unique_post_slug( $slug, $post_id, $post_status, $post_type, $post_parent ) {5465	if ( in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ), true )5466		|| ( 'inherit' === $post_status && 'revision' === $post_type ) || 'user_request' === $post_type5467	) {5468		return $slug;5469	}5470 5471	/**5472	 * Filters the post slug before it is generated to be unique.5473	 *5474	 * Returning a non-null value will short-circuit the5475	 * unique slug generation, returning the passed value instead.5476	 *5477	 * @since 5.1.05478	 *5479	 * @param string|null $override_slug Short-circuit return value.5480	 * @param string      $slug          The desired slug (post_name).5481	 * @param int         $post_id       Post ID.5482	 * @param string      $post_status   The post status.5483	 * @param string      $post_type     Post type.5484	 * @param int         $post_parent   Post parent ID.5485	 */5486	$override_slug = apply_filters( 'pre_wp_unique_post_slug', null, $slug, $post_id, $post_status, $post_type, $post_parent );5487	if ( null !== $override_slug ) {5488		return $override_slug;5489	}5490 5491	global $wpdb, $wp_rewrite;5492 5493	$original_slug = $slug;5494 5495	$feeds = $wp_rewrite->feeds;5496	if ( ! is_array( $feeds ) ) {5497		$feeds = array();5498	}5499 5500	if ( 'attachment' === $post_type ) {5501		// Attachment slugs must be unique across all types.5502		$check_sql       = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND ID != %d LIMIT 1";5503		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_id ) );5504 5505		/**5506		 * Filters whether the post slug would make a bad attachment slug.5507		 *5508		 * @since 3.1.05509		 *5510		 * @param bool   $bad_slug Whether the slug would be bad as an attachment slug.5511		 * @param string $slug     The post slug.5512		 */5513		$is_bad_attachment_slug = apply_filters( 'wp_unique_post_slug_is_bad_attachment_slug', false, $slug );5514 5515		if ( $post_name_check5516			|| in_array( $slug, $feeds, true ) || 'embed' === $slug5517			|| $is_bad_attachment_slug5518		) {5519			$suffix = 2;5520			do {5521				$alt_post_name   = _truncate_post_slug( $slug, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";5522				$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $alt_post_name, $post_id ) );5523				++$suffix;5524			} while ( $post_name_check );5525			$slug = $alt_post_name;5526		}5527	} elseif ( is_post_type_hierarchical( $post_type ) ) {5528		if ( 'nav_menu_item' === $post_type ) {5529			return $slug;5530		}5531 5532		/*5533		 * Page slugs must be unique within their own trees. Pages are in a separate5534		 * namespace than posts so page slugs are allowed to overlap post slugs.5535		 */5536		$check_sql       = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type IN ( %s, 'attachment' ) AND ID != %d AND post_parent = %d LIMIT 1";5537		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_type, $post_id, $post_parent ) );5538 5539		/**5540		 * Filters whether the post slug would make a bad hierarchical post slug.5541		 *5542		 * @since 3.1.05543		 *

Changelog

Introduced in 2.8.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.9.7 tag, from src/wp-includes/post.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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