Only do the description kung-fu on strings - fixes #17028

lib/private/app.php

@@ -1223,6 +1223,7 @@ class OC_App {
 		// just modify the description if it is available
 		// otherwise this will create a $data element with an empty 'description'
 		if (isset($data['description'])) {
+			if (is_string($data['description'])) {
 				// sometimes the description contains line breaks and they are then also
 				// shown in this way in the app management which isn't wanted as HTML
 				// manages line breaks itself
@@ -1240,6 +1241,9 @@ class OC_App {
 				// join the single paragraphs with a empty line in between
 				$data['description'] = implode("\n\n", $result);
 
+			} else {
+				$data['description'] = '';
+			}
 		}
 
 		return $data;

tests/lib/app.php

@@ -510,6 +510,10 @@ class Test_App extends \Test\TestCase {
 				['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   "]
 			],
+			[
+				['description' => [100, 'bla']],
+				['description' => ""]
+			],
 		];
 	}