Ticket #51794: 51794.2.diff

src/wp-includes/class-wp-query.php

@@ -915 +915 @@
                         }
 
                         if ( '' !== $qv['author_name'] ) {
-                                $this->is_author = true;
+                                if ( get_user_by( 'slug', $qv['author_name'] ) ) {
+                                        $this->is_author = true;
+                                } else {
+                                        $qv['error'] = '404';
+                                        $qv['author'] = $qv['author_name'];
+                                }
                         }
 
                         if ( ! empty( $qv['post_type'] ) && ! is_array( $qv['post_type'] ) ) {

tests/phpunit/tests/query.php

@@ -696 +696 @@
                 $this->assertSame( 'tax1', get_query_var( 'taxonomy' ) );
                 $this->assertSame( 'term1', get_query_var( 'term' ) );
         }
+
+        /**
+         * @ticket 51794
+         */
+        public function test_nonexistent_author_query_should_not_return_results() {
+                $p1 = self::factory()->post->create( array( 'post_author' => 0 ) );
+
+                $url = add_query_arg(
+                        array(
+                                'author_name' => 'thisuserdoesnotexist',
+                        ),
+                        '/'
+                );
+
+                $this->go_to( $url );
+
+                $matching_posts = wp_list_pluck( $GLOBALS['wp_query']->posts, 'ID' );
+
+                $this->assertTrue( $GLOBALS['wp_query']->is_404() );
+                $this->assertEmpty( $matching_posts );
+        }
+
 }