Ticket #40820: 40820.2.diff

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

@@ -267 +267 @@
                         }
                 }
 
+                if ( ! $this->template && $this->stylesheet === $this->headers['Template'] ) {
+                        /* translators: %s: Template */
+                        $this->errors = new WP_Error( 'theme_child_invalid', sprintf( __( 'The theme defines itself as its parent theme. Please check the "%s" header.' ), 'Template' ) );
+                        $this->cache_add( 'theme', array( 'headers' => $this->headers, 'errors' => $this->errors, 'stylesheet' => $this->stylesheet ) );
+
+                        return;
+                }
+
                 // (If template is set from cache [and there are no errors], we know it's good.)
                 if ( ! $this->template && ! ( $this->template = $this->headers['Template'] ) ) {
                         $this->template = $this->stylesheet;

tests/phpunit/tests/theme/WPTheme.php

@@ -140 +140 @@
                 $this->assertFalse( $theme->display( 'Tags' ) );
         }
 
+        /**
+         * @ticket 40820
+         */
+        function test_child_theme_with_itself_as_parent_should_appear_as_broken() {
+                $theme = new WP_Theme( 'child-parent-itself', $this->theme_root );
+                $errors = $theme->errors();
+                $this->assertWPError( $errors );
+                $this->assertEquals( 'theme_child_invalid', $errors->get_error_code() );
+        }
+
 
         /**
          * Enable a single theme on a network.

tests/phpunit/tests/theme/themeDir.php

@@ -175 +175 @@
          * @expectedDeprecated get_broken_themes
          */
         function test_broken_themes() {
-                $themes = get_themes();
-                $expected = array('broken-theme' => array('Name' => 'broken-theme', 'Title' => 'broken-theme', 'Description' => __('Stylesheet is missing.')));
+                $themes   = get_themes();
+
+                $expected = array(
+                        'broken-theme'           => array(
+                                'Name'        => 'broken-theme',
+                                'Title'       => 'broken-theme',
+                                'Description' => __( 'Stylesheet is missing.' ),
+                        ),
+                        'Child and Parent Theme' => array(
+                                'Name'        => 'Child and Parent Theme',
+                                'Title'       => 'Child and Parent Theme',
+                                'Description' => sprintf( __( 'The theme defines itself as its parent theme. Please check the "%s" header.' ), 'Template' ),
+                        ),
+                );
 
                 $this->assertEquals($expected, get_broken_themes() );
         }