Taxonomy: Check for empty term after DB sanitization in `wp_insert_term()`.

When inserting a new term in the database, `wp_insert_term()` will check if the term is empty and return a corresponding error.

Afterwards the term is sanitized and inserted in the database. However, there is a chance the term is empty after the DB sanitization.

This commit adds a check for an empty term name after the term is sanitized, returning an error in that case.

Follow-up to [5726], [8393].

Props fgiannar, kraftbj.
Fixes #59995.
Built from https://develop.svn.wordpress.org/trunk@57251


git-svn-id: http://core.svn.wordpress.org/trunk@56757 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/taxonomy.php

@@ -2434,6 +2434,11 @@ function wp_insert_term( $term, $taxonomy, $args = array() ) {
 	$description = wp_unslash( $args['description'] );
 	$parent      = (int) $args['parent'];
 
+	// Sanitization could clean the name to an empty string that must be checked again.
+	if ( '' === $name ) {
+		return new WP_Error( 'invalid_term_name', __( 'Invalid term name.' ) );
+	}
+
 	$slug_provided = ! empty( $args['slug'] );
 	if ( ! $slug_provided ) {
 		$slug = sanitize_title( $name );

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.5-alpha-57250';
+$wp_version = '6.5-alpha-57251';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.