Maybe you missed the difference between getHTML and getText... One returns HTML,...

diff --git a/includes/Exception.php b/includes/Exception.php
index 8a76b5f..3fea288 100644 (file)
--- a/includes/Exception.php
+++ b/includes/Exception.php
@@ -100,8 +100,8 @@ class MWException extends Exception {
                        return $this->getMessage() .
                                "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
                } else {
-                       return "<p>Set <tt>\$wgShowExceptionDetails = true;</tt> " .
-                               "in LocalSettings.php to show detailed debugging information.</p>";
+                       return "Set \$wgShowExceptionDetails = true; " .
+                               "in LocalSettings.php to show detailed debugging information.\n";
                }
        }