From 2549c49562272d25a4cca07c11ad6ba6a3cf1968 Mon Sep 17 00:00:00 2001
From: Timo Tijhof <ttijhof@wikimedia.org>
Date: Wed, 19 Sep 2012 02:24:35 +0200
Subject: [PATCH] (bug 40340) Fix cache issues with changing user groups

* migrateUserGroup.php: Call User::invalidateCache

* While at it, also fix the issue where User::clearInstanceCache
  did not clear cache for User::getGroups.

  Although it does clear the caches of methods used to calculate
  other group-related lists (such as User::getEffectiveGroups),
  the one for the query from user_groups was still cached in
  $this->mGroups.

  Presumably this was forgotten when this pattern was introduced
  as the instance cache precedes the user_group table.

Change-Id: I22abdba00f8ccf587a3d7696e57970ed4653afc8
---
 includes/User.php                |  1 +
 maintenance/migrateUserGroup.php | 31 ++++++++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/includes/User.php b/includes/User.php
index 91e75b530e..a6958c805f 100644
--- a/includes/User.php
+++ b/includes/User.php
@@ -1201,6 +1201,7 @@ class User {
 		$this->mRights = null;
 		$this->mEffectiveGroups = null;
 		$this->mImplicitGroups = null;
+		$this->mGroups = null;
 		$this->mOptions = null;
 		$this->mOptionsLoaded = false;
 		$this->mEditCount = null;
diff --git a/maintenance/migrateUserGroup.php b/maintenance/migrateUserGroup.php
index 496af7237b..f3e5957c60 100644
--- a/maintenance/migrateUserGroup.php
+++ b/maintenance/migrateUserGroup.php
@@ -55,7 +55,9 @@ class MigrateUserGroup extends Maintenance {
 		$blockEnd = $start + $this->mBatchSize - 1;
 		// Migrate users over in batches...
 		while ( $blockEnd <= $end ) {
+			$affected = 0;
 			$this->output( "Doing users $blockStart to $blockEnd\n" );
+
 			$dbw->begin( __METHOD__ );
 			$dbw->update( 'user_groups',
 				array( 'ug_group' => $newGroup ),
@@ -64,19 +66,42 @@ class MigrateUserGroup extends Maintenance {
 				__METHOD__,
 				array( 'IGNORE' )
 			);
-			$count += $dbw->affectedRows();
+			$affected += $dbw->affectedRows();
+			// Delete rows that the UPDATE operation above had to ignore.
+			// This happens when a user is in both the old and new group.
+			// Updating the row for the old group membership failed since
+			// user/group is UNIQUE.
 			$dbw->delete( 'user_groups',
 				array( 'ug_group' => $oldGroup,
 					"ug_user BETWEEN $blockStart AND $blockEnd" ),
 				__METHOD__
 			);
-			$count += $dbw->affectedRows();
+			$affected += $dbw->affectedRows();
 			$dbw->commit( __METHOD__ );
+
+			// Clear cache for the affected users (bug 40340)
+			if ( $affected > 0 ) {
+				// XXX: This also invalidates cache of unaffected users that
+				// were in the new group and not in the group.
+				$res = $dbw->select( 'user_groups', 'ug_user',
+					array( 'ug_group' => $newGroup,
+						"ug_user BETWEEN $blockStart AND $blockEnd" ),
+					__METHOD__
+				);
+				if ( $res !== false ) {
+					foreach ( $res as $row ) {
+						$user = User::newFromId( $row->ug_user );
+						$user->invalidateCache();
+					}
+				}
+			}
+
+			$count += $affected;
 			$blockStart += $this->mBatchSize;
 			$blockEnd += $this->mBatchSize;
 			wfWaitForSlaves();
 		}
-		$this->output( "Done! $count user(s) in group '$oldGroup' are now in '$newGroup' instead.\n" );
+		$this->output( "Done! $count users in group '$oldGroup' are now in '$newGroup' instead.\n" );
 	}
 }
 
-- 
2.20.1