From 74aa6b07db7ff346bab4d9ef1cb8871b6c8550cb Mon Sep 17 00:00:00 2001
From: =?utf8?q?Gerg=C5=91=20Tisza?= <gtisza@wikimedia.org>
Date: Thu, 24 Nov 2016 05:19:05 +0000
Subject: [PATCH] Improve logging of exceptions which are not thrown but
 attached to context

Bug: T151290
Change-Id: I9cc9f54c2987cf960343b5eca2a1c6d006b892bf
---
 .../logger/monolog/LogstashFormatter.php      | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/includes/debug/logger/monolog/LogstashFormatter.php b/includes/debug/logger/monolog/LogstashFormatter.php
index 553cbf61c4..09ed7555db 100644
--- a/includes/debug/logger/monolog/LogstashFormatter.php
+++ b/includes/debug/logger/monolog/LogstashFormatter.php
@@ -6,6 +6,7 @@ namespace MediaWiki\Logger\Monolog;
  * LogstashFormatter squashes the base message array and the context and extras subarrays into one.
  * This can result in unfortunately named context fields overwriting other data (T145133).
  * This class modifies the standard LogstashFormatter to rename such fields and flag the message.
+ * Also changes exception JSON-ification which is done poorly by the standard class.
  *
  * Compatible with Monolog 1.x only.
  *
@@ -80,4 +81,31 @@ class LogstashFormatter extends \Monolog\Formatter\LogstashFormatter {
 		}
 		return $fields;
 	}
+
+	/**
+	 * Use a more user-friendly trace format than NormalizerFormatter
+	 * @param \Exception|\Throwable $e
+	 * @return array
+	 */
+	protected function normalizeException( $e ) {
+		if ( !$e instanceof \Exception && !$e instanceof \Throwable ) {
+			throw new \InvalidArgumentException( 'Exception/Throwable expected, got '
+				. gettype( $e ) . ' / ' . get_class( $e ) );
+		}
+
+		$data = [
+			'class' => get_class( $e ),
+			'message' => $e->getMessage(),
+			'code' => $e->getCode(),
+			'file' => $e->getFile() . ':' . $e->getLine(),
+			'trace' => \MWExceptionHandler::getRedactedTraceAsString( $e ),
+		];
+
+		$previous = $e->getPrevious();
+		if ( $previous ) {
+			$data['previous'] = $this->normalizeException( $previous );
+		}
+
+		return $data;
+	}
 }
-- 
2.20.1