Fatal error in wp_insert_term() when the term name is not a string

src/wp-includes/class-wp-xmlrpc-server.php

@@ -1666,6 +1666,10 @@ protected function _insert_post( $user, $content_struct ) {
 
 					$term_names = $post_data['terms_names'][ $taxonomy ];
 					foreach ( $term_names as $term_name ) {
+						if ( ! is_string( $term_name ) ) {
+							return new IXR_Error( 403, __( 'Invalid term name.' ) );
+						}
+
 						if ( in_array( $term_name, $ambiguous_terms, true ) ) {
 							return new IXR_Error( 401, __( 'Ambiguous term name used in a hierarchical taxonomy. Please use term ID instead.' ) );
 						}

src/wp-includes/taxonomy.php

@@ -2501,6 +2501,7 @@ function wp_get_object_terms( $object_ids, $taxonomies, $args = array() ) {
  * @global wpdb $wpdb WordPress database abstraction object.
  *
  * @since 2.3.0
+ * @since 7.2.0 A non-scalar `$term` now returns a WP_Error instead of causing a fatal error.
  *
  * @param string       $term     The term name to add.
  * @param string       $taxonomy The taxonomy to which to add the term.
@@ -2558,7 +2559,7 @@ function wp_insert_term( $term, $taxonomy, $args = array() ) {
 		return new WP_Error( 'invalid_term_id', __( 'Invalid term ID.' ) );
 	}
 
-	if ( '' === trim( $term ) ) {
+	if ( ! is_scalar( $term ) || '' === trim( $term ) ) {
 		return new WP_Error( 'empty_term_name', __( 'A name is required for this term.' ) );
 	}
 

tests/phpunit/tests/term/wpInsertTerm.php

@@ -76,6 +76,62 @@ public function test_wp_insert_term_term_trims_to_empty_string() {
 		$this->assertSame( 'empty_term_name', $found->get_error_code() );
 	}
 
+	/**
+	 * Tests that a non-scalar term name returns a WP_Error instead of causing a fatal error.
+	 *
+	 * @ticket 66108
+	 *
+	 * @dataProvider data_wp_insert_term_non_scalar_term_name
+	 *
+	 * @param mixed $term The term name to insert.
+	 */
+	public function test_wp_insert_term_non_scalar_term_name( $term ): void {
+		$found = wp_insert_term( $term, 'post_tag' );
+
+		$this->assertWPError( $found );
+		$this->assertSame( 'empty_term_name', $found->get_error_code() );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array<string, array{mixed}>
+	 */
+	public function data_wp_insert_term_non_scalar_term_name(): array {
+		return array(
+			'array'  => array( array( 'foo', 'bar' ) ),
+			'object' => array( new stdClass() ),
+		);
+	}
+
+	/**
+	 * Tests that a numeric term name is inserted and stored as its string form.
+	 *
+	 * @ticket 66108
+	 *
+	 * @dataProvider data_wp_insert_term_numeric_term_name
+	 *
+	 * @param int|float $term The term name to insert.
+	 */
+	public function test_wp_insert_term_numeric_term_name( $term ): void {
+		$found = wp_insert_term( $term, 'post_tag' );
+
+		$this->assertNotWPError( $found );
+		$this->assertSame( (string) $term, get_term( $found['term_id'], 'post_tag' )->name );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array<string, array{int|float}>
+	 */
+	public function data_wp_insert_term_numeric_term_name(): array {
+		return array(
+			'integer' => array( 2024 ),
+			'float'   => array( 1.5 ),
+		);
+	}
+
 	public function test_wp_insert_term_parent_does_not_exist() {
 		$found = wp_insert_term(
 			'foo',

tests/phpunit/tests/xmlrpc/wp/newPost.php

@@ -345,6 +345,43 @@ public function test_terms_names() {
 		$this->assertSame( 401, $result2->code );
 	}
 
+	/**
+	 * Tests that a non-string term name in `terms_names` returns an error instead of causing a fatal error.
+	 *
+	 * @ticket 66108
+	 *
+	 * @dataProvider data_terms_names_non_string_term_name
+	 *
+	 * @param mixed $term_name The term name to send.
+	 */
+	public function test_terms_names_non_string_term_name( $term_name ): void {
+		$this->make_user_by_role( 'editor' );
+
+		$post   = array(
+			'post_title'  => 'Test',
+			'terms_names' => array(
+				'post_tag' => array( $term_name ),
+			),
+		);
+		$result = $this->myxmlrpcserver->wp_newPost( array( 1, 'editor', 'editor', $post ) );
+
+		$this->assertIXRError( $result );
+		$this->assertSame( 403, $result->code );
+		$this->assertSame( 'Invalid term name.', $result->message );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array<string, array{mixed}>
+	 */
+	public function data_terms_names_non_string_term_name(): array {
+		return array(
+			'array'   => array( array( 'foo', 'bar' ) ),
+			'integer' => array( 123 ),
+		);
+	}
+
 	/**
 	 * @ticket 28601
 	 */