From b964607dcea62606ed0e596d1d433cacaf68b9fd Mon Sep 17 00:00:00 2001
From: Ed Sanders <esanders@wikimedia.org>
Date: Fri, 30 Mar 2018 20:56:59 +0100
Subject: [PATCH] Use fallback languages in ResourceLoaderImage

Bug: T191120
Change-Id: Ic72aead466c12d344bac359654e6dcc7f0e5c8cb
---
 .../resourceloader/ResourceLoaderImage.php    | 24 +++++++++++++++----
 .../ResourceLoaderImageTest.php               |  4 ++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/includes/resourceloader/ResourceLoaderImage.php b/includes/resourceloader/ResourceLoaderImage.php
index 072ae7944b..d38a175008 100644
--- a/includes/resourceloader/ResourceLoaderImage.php
+++ b/includes/resourceloader/ResourceLoaderImage.php
@@ -130,13 +130,27 @@ class ResourceLoaderImage {
 		$desc = $this->descriptor;
 		if ( is_string( $desc ) ) {
 			return $this->basePath . '/' . $desc;
-		} elseif ( isset( $desc['lang'][$context->getLanguage()] ) ) {
-			return $this->basePath . '/' . $desc['lang'][$context->getLanguage()];
-		} elseif ( isset( $desc[$context->getDirection()] ) ) {
+		}
+		if ( isset( $desc['lang'] ) ) {
+			$contextLang = $context->getLanguage();
+			if ( isset( $desc['lang'][$contextLang] ) ) {
+				return $this->basePath . '/' . $desc['lang'][$contextLang];
+			}
+			$fallbacks = Language::getFallbacksFor( $contextLang );
+			foreach ( $fallbacks as $lang ) {
+				// Images will fallback to 'default' instead of 'en', except for 'en-*' variants
+				if (
+					( $lang !== 'en' || substr( $contextLang, 0, 3 ) === 'en-' ) &&
+					isset( $desc['lang'][$lang] )
+				) {
+					return $this->basePath . '/' . $desc['lang'][$lang];
+				}
+			}
+		}
+		if ( isset( $desc[$context->getDirection()] ) ) {
 			return $this->basePath . '/' . $desc[$context->getDirection()];
-		} else {
-			return $this->basePath . '/' . $desc['default'];
 		}
+		return $this->basePath . '/' . $desc['default'];
 	}
 
 	/**
diff --git a/tests/phpunit/includes/resourceloader/ResourceLoaderImageTest.php b/tests/phpunit/includes/resourceloader/ResourceLoaderImageTest.php
index 838d2c087f..35c3ef6454 100644
--- a/tests/phpunit/includes/resourceloader/ResourceLoaderImageTest.php
+++ b/tests/phpunit/includes/resourceloader/ResourceLoaderImageTest.php
@@ -39,7 +39,9 @@ class ResourceLoaderImageTest extends ResourceLoaderTestCase {
 			[ 'mno', 'ar', 'mno-rtl.svg' ],
 			[ 'mno', 'he', 'mno-ltr.svg' ],
 			[ 'pqr', 'en', 'pqr-b.svg' ],
+			[ 'pqr', 'en-gb', 'pqr-b.svg' ],
 			[ 'pqr', 'de', 'pqr-f.svg' ],
+			[ 'pqr', 'de-formal', 'pqr-f.svg' ],
 			[ 'pqr', 'ar', 'pqr-f.svg' ],
 			[ 'pqr', 'fr', 'pqr-a.svg' ],
 			[ 'pqr', 'he', 'pqr-a.svg' ],
@@ -53,7 +55,9 @@ class ResourceLoaderImageTest extends ResourceLoaderTestCase {
 	public function testGetPath( $imageName, $languageCode, $path ) {
 		static $dirMap = [
 			'en' => 'ltr',
+			'en-gb' => 'ltr',
 			'de' => 'ltr',
+			'de-formal' => 'ltr',
 			'fr' => 'ltr',
 			'he' => 'rtl',
 			'ar' => 'rtl',
-- 
2.20.1