Ticket #51390: 51390.2.patch

src/wp-includes/theme.php

@@ -2517 +2517 @@
                                 unset( $post_formats['standard'] );
 
                                 $args[0] = array_intersect( $args[0], array_keys( $post_formats ) );
+                        } else {
+                                _doing_it_wrong( "add_theme_support( 'post-formats' )", __( 'You need to pass an array of types.' ), '5.6.0' );
+                                return false;
                         }
                         break;
 

tests/phpunit/tests/post/formats.php

@@ -8 +8 @@
                 parent::setUp();
         }
 
+        function test_post_format_doing_it_wrong() {
+                $this->setExpectedIncorrectUsage( "add_theme_support( 'post-formats' )" );
+
+                // The second parameter should be an array
+                $this->assertFalse( add_theme_support( 'post-formats' ) );
+        }
+
         function test_set_get_post_format_for_post() {
                 $post_id = self::factory()->post->create();