Source

File: wp-includes/post.php

function wp_delete_post( $postid = 0, $force_delete = false ) {
	global $wpdb;

	$post = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE ID = %d", $postid ) );

	if ( ! $post ) {
		return $post;
	}

	$post = get_post( $post );

	if ( ! $force_delete && ( 'post' === $post->post_type || 'page' === $post->post_type ) && 'trash' !== get_post_status( $postid ) && EMPTY_TRASH_DAYS ) {
		return wp_trash_post( $postid );
	}

	if ( 'attachment' === $post->post_type ) {
		return wp_delete_attachment( $postid, $force_delete );
	}

	/**
	 * Filters whether a post deletion should take place.
	 *
	 * @since 4.4.0
	 *
	 * @param bool|null $delete       Whether to go forward with deletion.
	 * @param WP_Post   $post         Post object.
	 * @param bool      $force_delete Whether to bypass the Trash.
	 */
	$check = apply_filters( 'pre_delete_post', null, $post, $force_delete );
	if ( null !== $check ) {
		return $check;
	}

	/**
	 * Fires before a post is deleted, at the start of wp_delete_post().
	 *
	 * @since 3.2.0
	 * @since 5.5.0 Added the `$post` parameter.
	 *
	 * @see wp_delete_post()
	 *
	 * @param int     $postid Post ID.
	 * @param WP_Post $post   Post object.
	 */
	do_action( 'before_delete_post', $postid, $post );

	delete_post_meta( $postid, '_wp_trash_meta_status' );
	delete_post_meta( $postid, '_wp_trash_meta_time' );

	wp_delete_object_term_relationships( $postid, get_object_taxonomies( $post->post_type ) );

	$parent_data  = array( 'post_parent' => $post->post_parent );
	$parent_where = array( 'post_parent' => $postid );

	if ( is_post_type_hierarchical( $post->post_type ) ) {
		// Point children of this page to its parent, also clean the cache of affected children.
		$children_query = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_parent = %d AND post_type = %s", $postid, $post->post_type );
		$children       = $wpdb->get_results( $children_query );
		if ( $children ) {
			$wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => $post->post_type ) );
		}
	}

	// Do raw query. wp_get_post_revisions() is filtered.
	$revision_ids = $wpdb->get_col( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE post_parent = %d AND post_type = 'revision'", $postid ) );
	// Use wp_delete_post (via wp_delete_post_revision) again. Ensures any meta/misplaced data gets cleaned up.
	foreach ( $revision_ids as $revision_id ) {
		wp_delete_post_revision( $revision_id );
	}

	// Point all attachments to this post up one level.
	$wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => 'attachment' ) );

	wp_defer_comment_counting( true );

	$comment_ids = $wpdb->get_col( $wpdb->prepare( "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = %d", $postid ) );
	foreach ( $comment_ids as $comment_id ) {
		wp_delete_comment( $comment_id, true );
	}

	wp_defer_comment_counting( false );

	$post_meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d ", $postid ) );
	foreach ( $post_meta_ids as $mid ) {
		delete_metadata_by_mid( 'post', $mid );
	}

	/**
	 * Fires immediately before a post is deleted from the database.
	 *
	 * @since 1.2.0
	 * @since 5.5.0 Added the `$post` parameter.
	 *
	 * @param int     $postid Post ID.
	 * @param WP_Post $post   Post object.
	 */
	do_action( 'delete_post', $postid, $post );

	$result = $wpdb->delete( $wpdb->posts, array( 'ID' => $postid ) );
	if ( ! $result ) {
		return false;
	}

	/**
	 * Fires immediately after a post is deleted from the database.
	 *
	 * @since 2.2.0
	 * @since 5.5.0 Added the `$post` parameter.
	 *
	 * @param int     $postid Post ID.
	 * @param WP_Post $post   Post object.
	 */
	do_action( 'deleted_post', $postid, $post );

	clean_post_cache( $post );

	if ( is_post_type_hierarchical( $post->post_type ) && $children ) {
		foreach ( $children as $child ) {
			clean_post_cache( $child );
		}
	}

	wp_clear_scheduled_hook( 'publish_future_post', array( $postid ) );

	/**
	 * Fires after a post is deleted, at the conclusion of wp_delete_post().
	 *
	 * @since 3.2.0
	 * @since 5.5.0 Added the `$post` parameter.
	 *
	 * @see wp_delete_post()
	 *
	 * @param int     $postid Post ID.
	 * @param WP_Post $post   Post object.
	 */
	do_action( 'after_delete_post', $postid, $post );

	return $post;
}