Ticket #30921: 30921.diff

src/wp-admin/includes/class-wp-upgrader.php

@@ -405 +405 @@
                  * destination directory (WP_PLUGIN_DIR / wp-content/themes) intending
                  * to copy the directory into the directory, whilst they pass the source
                  * as the actual files to copy.
                  */
                 $protected_directories = array( ABSPATH, WP_CONTENT_DIR, WP_PLUGIN_DIR, WP_CONTENT_DIR . '/themes' );
 
                 if ( is_array( $wp_theme_directories ) ) {
                         $protected_directories = array_merge( $protected_directories, $wp_theme_directories );
                 }
                 if ( in_array( $destination, $protected_directories ) ) {
                         $remote_destination = trailingslashit( $remote_destination ) . trailingslashit( basename( $source ) );
                         $destination = trailingslashit( $destination ) . trailingslashit( basename( $source ) );
                 }
 
                 if ( $clear_destination ) {
-                        //We're going to clear the destination if there's something there
+                        // We're going to clear the destination if there's something there
                         $this->skin->feedback('remove_old');
+
                         $removed = true;
                         if ( $wp_filesystem->exists( $remote_destination ) ) {
-                                $removed = $wp_filesystem->delete( $remote_destination, true );
+                                // Check all files are writable before attempting to clear the destination
+                                $unwritable_files = array();
+
+                                $_files = $wp_filesystem->dirlist( $remote_destination, true, true );
+                                // Flatten the resulting array
+                                while ( $f = each( $_files ) ) {
+                                        $file = $f['value'];
+                                        $name = $f['key'];
+
+                                        if ( ! isset( $file['files'] ) ) {
+                                                continue;
+                                        }
+
+                                        foreach ( $file['files'] as $filename => $details ) {
+                                                $_files[ $name . '/' . $filename ] = $details;
+                                        }
+                                }
+
+                                // Check writability
+                                foreach ( $_files as $filename => $file_details ) {
+                                        if ( ! $wp_filesystem->is_writable( $remote_destination . $filename ) ) {
+                                                $unwritable_files[] = $filename;
+                                        }
+                                }
+
+                                if ( empty( $unwritable_files ) ) {
+                                        $removed = $wp_filesystem->delete( $remote_destination, true );
+                                } else {
+                                        $removed = new WP_Error( 'unwritable_files', 'Some files are unwritable, abort abort!', $unwritable_files );
+                                }
                         }
 
                         /**
                          * Filter whether the upgrader cleared the destination.
                          *
                          * @since 2.8.0
                          *
                          * @param bool   $removed            Whether the destination was cleared.
                          * @param string $local_destination  The local package destination.
                          * @param string $remote_destination The remote package destination.
                          * @param array  $hook_extra         Extra arguments passed to hooked filters.
                          */
                         $removed = apply_filters( 'upgrader_clear_destination', $removed, $local_destination, $remote_destination, $args['hook_extra'] );
 
                         if ( is_wp_error($removed) ) {