From 33d4dfea0f465df9a10c7adfbbe22835ef8ba543 Mon Sep 17 00:00:00 2001
From: Timo Tijhof <krinklemail@gmail.com>
Date: Sat, 31 Aug 2019 22:08:35 +0100
Subject: [PATCH] registration: Avoid redundant LBYL check in
 ExtensionRegistry::queue()

Avoids extra I/O, and with that the race condition it holds.

Bug: T187154
Change-Id: I46ded196835bcd677fe41da4890fc7998a0b4d17
---
 includes/registration/ExtensionRegistry.php           | 11 +++++------
 .../includes/registration/ExtensionRegistryTest.php   |  2 +-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/includes/registration/ExtensionRegistry.php b/includes/registration/ExtensionRegistry.php
index 3e65f6c1ba..5663487c87 100644
--- a/includes/registration/ExtensionRegistry.php
+++ b/includes/registration/ExtensionRegistry.php
@@ -1,6 +1,7 @@
 <?php
 
 use Composer\Semver\Semver;
+use Wikimedia\AtEase\AtEase;
 use Wikimedia\ScopedCallback;
 use MediaWiki\Shell\Shell;
 use MediaWiki\ShellDisabledError;
@@ -126,15 +127,13 @@ class ExtensionRegistry {
 
 		$mtime = $wgExtensionInfoMTime;
 		if ( $mtime === false ) {
-			if ( file_exists( $path ) ) {
-				$mtime = filemtime( $path );
-			} else {
-				throw new Exception( "$path does not exist!" );
-			}
+			AtEase::suppressWarnings();
+			$mtime = filemtime( $path );
+			AtEase::restoreWarnings();
 			// @codeCoverageIgnoreStart
 			if ( $mtime === false ) {
 				$err = error_get_last();
-				throw new Exception( "Couldn't stat $path: {$err['message']}" );
+				throw new Exception( "Unable to open file $path: {$err['message']}" );
 				// @codeCoverageIgnoreEnd
 			}
 		}
diff --git a/tests/phpunit/includes/registration/ExtensionRegistryTest.php b/tests/phpunit/includes/registration/ExtensionRegistryTest.php
index 5de1b0cb4b..106cca388c 100644
--- a/tests/phpunit/includes/registration/ExtensionRegistryTest.php
+++ b/tests/phpunit/includes/registration/ExtensionRegistryTest.php
@@ -19,7 +19,7 @@ class ExtensionRegistryTest extends MediaWikiTestCase {
 		$path = __DIR__ . '/doesnotexist.json';
 		$this->setExpectedException(
 			Exception::class,
-			"$path does not exist!"
+			"file $path"
 		);
 		$registry->queue( $path );
 	}
-- 
2.20.1