Use UTF-8 mode for preg_split and preg_replace

Otherwise a single application with a description containing a non compliant character can break the whole ownCloud appstore. This is for example https://apps.owncloud.com/content/show.php?content=149553

Fixes https://github.com/owncloud/core/issues/17101#issuecomment-117365224

lib/private/app.php

@@ -1228,17 +1228,18 @@ class OC_App {
 			// manages line breaks itself
 
 			// first of all we split on empty lines
-			$paragraphs = preg_split("!\n[[:space:]]*\n!m", $data['description']);
+			$paragraphs = preg_split("!\n[[:space:]]*\n!mu", $data['description']);
 
 			$result = [];
 			foreach ($paragraphs as $value) {
 				// replace multiple whitespace (tabs, space, newlines) inside a paragraph
 				// with a single space - also trims whitespace
-				$result[] = trim(preg_replace('![[:space:]]+!m', ' ', $value));
+				$result[] = trim(preg_replace('![[:space:]]+!mu', ' ', $value));
 			}
 
 			// join the single paragraphs with a empty line in between
 			$data['description'] = implode("\n\n", $result);
+
 		}
 
 		return $data;

tests/lib/app.php

@@ -502,6 +502,10 @@ class Test_App extends \Test\TestCase {
 				['description' => " \t  This is a multiline \n test with \n \t   some new lines   "],
 				['description' => "This is a multiline test with some new lines"]
 			],
+			[
+				['description' => hex2bin('5065726d657420646520732761757468656e7469666965722064616e732070697769676f20646972656374656d656e74206176656320736573206964656e74696669616e7473206f776e636c6f75642073616e73206c65732072657461706572206574206d657420c3a0206a6f757273206365757820636920656e20636173206465206368616e67656d656e74206465206d6f742064652070617373652e0d0a0d')],
+				['description' => "Permet de s'authentifier dans piwigo directement avec ses identifiants owncloud sans les retaper et met à jours ceux ci en cas de changement de mot de passe."]
+			],
 			[
 				['not-a-description' => " \t  This is a multiline \n test with \n \t   some new lines   "],
 				['not-a-description' => " \t  This is a multiline \n test with \n \t   some new lines   "]
@@ -513,9 +517,11 @@ class Test_App extends \Test\TestCase {
 	 * Test app info parser
 	 *
 	 * @dataProvider appDataProvider
+	 * @param array $data
+	 * @param array $expected
 	 */
-	public function testParseAppInfo($data, $expected) {
-		$this->assertEquals($expected, \OC_App::parseAppInfo($data));
+	public function testParseAppInfo(array $data, array $expected) {
+		$this->assertSame($expected, \OC_App::parseAppInfo($data));
 	}
 }