Merge "Added CAS-style logic to User::saveSettings as a final sanity check"

[lhc/web/wiklou.git] / includes / User.php

diff --git a/includes/User.php b/includes/User.php
index ecb31ba..4ada6b1 100644 (file)
--- a/includes/User.php
+++ b/includes/User.php
@@ -452,7 +452,7 @@ class User implements IDBAccessObject {
                // The cache needs good consistency due to its high TTL, so the user
                // should have been loaded from the master to avoid lag amplification.
                if ( !( $this->queryFlagsUsed & self::READ_LATEST ) ) {
-                       wfWarn( "Cannot save slave-loaded User object data to cache." );
+                       wfWarn( "Cannot cache slave-loaded User object with ID '{$this->mId}'." );
                        return;
                }
 
@@ -3604,16 +3604,21 @@ class User implements IDBAccessObject {
                $this->load();
                $this->loadPasswords();
                if ( 0 == $this->mId ) {
-                       return;
+                       return; // anon
                }
 
                // This method is for updating existing users, so the user should
                // have been loaded from the master to begin with to avoid problems.
                if ( !( $this->queryFlagsUsed & self::READ_LATEST ) ) {
-                       wfWarn( "Attempting to save slave-loaded User object data." );
+                       wfWarn( "Attempting to save slave-loaded User object with ID '{$this->mId}'." );
                }
 
+               // Get a new user_touched that is higher than the old one.
+               // This will be used for a CAS check as a last-resort safety
+               // check against race conditions and slave lag.
+               $oldTouched = $this->mTouched;
                $this->mTouched = $this->newTouchedTimestamp();
+
                if ( !$wgAuth->allowSetLocalPassword() ) {
                        $this->mPassword = self::getPasswordFactory()->newFromCiphertext( null );
                }
@@ -3634,10 +3639,22 @@ class User implements IDBAccessObject {
                                'user_email_token_expires' => $dbw->timestampOrNull( $this->mEmailTokenExpires ),
                                'user_password_expires' => $dbw->timestampOrNull( $this->mPasswordExpires ),
                        ), array( /* WHERE */
-                               'user_id' => $this->mId
+                               'user_id' => $this->mId,
+                               'user_touched' => $dbw->timestamp( $oldTouched ) // CAS check
                        ), __METHOD__
                );
 
+               if ( !$dbw->affectedRows() ) {
+                       // User was changed in the meantime or loaded with stale data
+                       MWExceptionHandler::logException( new MWException(
+                               "CAS update failed on user_touched for user ID '{$this->mId}'."
+                       ) );
+                       // Maybe the problem was a missed cache update; clear it to be safe
+                       $this->clearSharedCache();
+
+                       return;
+               }
+
                $this->saveOptions();
 
                Hooks::run( 'UserSaveSettings', array( $this ) );