From 6aaf0f9359ab1bd2bfd615974cf6f65a698551aa Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 8 Jun 2016 10:25:25 -0700
Subject: [PATCH] Avoid getWithSetCallback() warnings on unversioned key
 migration

If an unversioned key is present, this generated a warning
previously.

Bug: T137244
Change-Id: I92df9b9fe0436348b5b27e684d239238d57c9b5f
---
 includes/libs/objectcache/WANObjectCache.php | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index f12cb4ccbc..45713cc814 100644
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -800,7 +800,15 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
 					$key,
 					$ttl,
 					function ( $oldValue, &$ttl, &$setOpts ) use ( $callback, $version ) {
-						$oldData = $oldValue ? $oldValue[self::VFLD_DATA] : false;
+						if ( is_array( $oldValue )
+							&& array_key_exists( self::VFLD_DATA, $oldValue )
+						) {
+							$oldData = $oldValue[self::VFLD_DATA];
+						} else {
+							// VFLD_DATA is not set if an old, unversioned, key is present
+							$oldData = false;
+						}
+
 						return [
 							self::VFLD_DATA => $callback( $oldData, $ttl, $setOpts ),
 							self::VFLD_VERSION => $version
-- 
2.20.1