From 08b0462fdc056e39d12d826c2cfc6bb0d6f08253 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Fri, 28 Jun 2019 19:11:43 -0700
Subject: [PATCH] Make UserEditCountUpdate::doUpdate avoid comparing IDatabase
 instances

Also make User::initEditCountInternal take the specific DB handle that
was waited on for replication. This shouldn't make a difference but makes
things more explicit.

Change-Id: Ibb8e083406eb4f4453afce94a2b33450239fce94
---
 includes/deferred/UserEditCountUpdate.php | 17 ++++++++---------
 includes/user/User.php                    |  9 ++++-----
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/includes/deferred/UserEditCountUpdate.php b/includes/deferred/UserEditCountUpdate.php
index e9ebabb643..157c20b0dc 100644
--- a/includes/deferred/UserEditCountUpdate.php
+++ b/includes/deferred/UserEditCountUpdate.php
@@ -82,16 +82,15 @@ class UserEditCountUpdate implements DeferrableUpdate, MergeableUpdate {
 				$affectedInstances = $info['instances'];
 				// Lazy initialization check...
 				if ( $dbw->affectedRows() == 0 ) {
-					// No rows will be "affected" if user_editcount is NULL.
-					// Check if the generic "replica" connection is not the master.
+					// The user_editcount is probably NULL (e.g. not initialized).
+					// Since this update runs after the new revisions were committed,
+					// wait for the replica DB to catch up so they will be counted.
 					$dbr = $lb->getConnection( DB_REPLICA );
-					if ( $dbr !== $dbw ) {
-						// This method runs after the new revisions were committed.
-						// Wait for the replica to catch up so they will all be counted.
-						$dbr->flushSnapshot( $fname );
-						$lb->waitForMasterPos( $dbr );
-					}
-					$affectedInstances[0]->initEditCountInternal();
+					// If $dbr is actually the master DB, then clearing the snapshot is
+					// is harmless and waitForMasterPos() will just no-op.
+					$dbr->flushSnapshot( $fname );
+					$lb->waitForMasterPos( $dbr );
+					$affectedInstances[0]->initEditCountInternal( $dbr );
 				}
 				$newCount = (int)$dbw->selectField(
 					'user',
diff --git a/includes/user/User.php b/includes/user/User.php
index 97d47023f7..965cd84279 100644
--- a/includes/user/User.php
+++ b/includes/user/User.php
@@ -3464,7 +3464,7 @@ class User implements IDBAccessObject, UserIdentity {
 
 			if ( $count === null ) {
 				// it has not been initialized. do so.
-				$count = $this->initEditCountInternal();
+				$count = $this->initEditCountInternal( $dbr );
 			}
 			$this->mEditCount = $count;
 		}
@@ -5024,14 +5024,13 @@ class User implements IDBAccessObject, UserIdentity {
 	/**
 	 * Initialize user_editcount from data out of the revision table
 	 *
-	 * This method should not be called outside User/UserEditCountUpdate
-	 *
+	 * @internal This method should not be called outside User/UserEditCountUpdate
+	 * @param IDatabase $dbr Replica database
 	 * @return int Number of edits
 	 */
-	public function initEditCountInternal() {
+	public function initEditCountInternal( IDatabase $dbr ) {
 		// Pull from a replica DB to be less cruel to servers
 		// Accuracy isn't the point anyway here
-		$dbr = wfGetDB( DB_REPLICA );
 		$actorWhere = ActorMigration::newMigration()->getWhere( $dbr, 'rev_user', $this );
 		$count = (int)$dbr->selectField(
 			[ 'revision' ] + $actorWhere['tables'],
-- 
2.20.1