Additional error checking for scratchpads

syntax/scratchpad.php

@@ -88,8 +88,22 @@ class syntax_plugin_luxtools_scratchpad extends SyntaxPlugin
         }
 
         $text = '';
-        if (@is_file($filePath) && @is_readable($filePath)) {
-            $text = (string)io_readFile($filePath, false);
+        $exists = @is_file($filePath);
+
+        // If the scratchpad file is missing, render empty content. This allows
+        // creating the file via the inline editor without showing an error.
+        if ($exists) {
+            if (!@is_readable($filePath)) {
+                $this->renderError($renderer, 'scratchpad_err_unreadable');
+                return true;
+            }
+
+            $read = io_readFile($filePath, false);
+            if ($read === false) {
+                $this->renderError($renderer, 'scratchpad_err_unreadable');
+                return true;
+            }
+            $text = (string)$read;
         }
 
         if ($format === 'odt') {