App dependencies are now analysed on app enable as well - not only on app install.

lib/private/App/DependencyAnalyzer.php

@@ -223,6 +223,9 @@ class DependencyAnalyzer {
 		if (!is_array($libs)) {
 			$libs = [$libs];
 		}
+		if (isset($libs['@value'])) {
+			$libs = [$libs];
+		}
 		foreach ($libs as $lib) {
 			$libName = $this->getValue($lib);
 			$libVersion = $this->platform->getLibraryVersion($libName);

lib/private/legacy/app.php

@@ -329,6 +329,13 @@ class OC_App {
 		self::$enabledAppsCache = []; // flush
 		if (!Installer::isInstalled($app)) {
 			$app = self::installApp($app);
+		} else {
+			// check for required dependencies
+			$config = \OC::$server->getConfig();
+			$l = \OC::$server->getL10N('core');
+			$info = self::getAppInfo($app);
+
+			self::checkAppDependencies($config, $l, $info);
 		}
 
 		$appManager = \OC::$server->getAppManager();
@@ -1171,16 +1178,7 @@ class OC_App {
 			}
 
 			// check for required dependencies
-			$dependencyAnalyzer = new DependencyAnalyzer(new Platform($config), $l);
-			$missing = $dependencyAnalyzer->analyze($info);
-			if (!empty($missing)) {
-				$missingMsg = join(PHP_EOL, $missing);
-				throw new \Exception(
-					$l->t('App "%s" cannot be installed because the following dependencies are not fulfilled: %s',
-						[$info['name'], $missingMsg]
-					)
-				);
-			}
+			self::checkAppDependencies($config, $l, $info);
 
 			$config->setAppValue($app, 'enabled', 'yes');
 			if (isset($appData['id'])) {
@@ -1351,4 +1349,23 @@ class OC_App {
 
 		return $data;
 	}
+
+	/**
+	 * @param $config
+	 * @param $l
+	 * @param $info
+	 * @throws Exception
+	 */
+	protected static function checkAppDependencies($config, $l, $info) {
+		$dependencyAnalyzer = new DependencyAnalyzer(new Platform($config), $l);
+		$missing = $dependencyAnalyzer->analyze($info);
+		if (!empty($missing)) {
+			$missingMsg = join(PHP_EOL, $missing);
+			throw new \Exception(
+				$l->t('App "%s" cannot be installed because the following dependencies are not fulfilled: %s',
+					[$info['name'], $missingMsg]
+				)
+			);
+		}
+	}
 }

tests/lib/App/DependencyAnalyzerTest.php

@@ -9,7 +9,7 @@
 
 namespace Test\App;
 
-use OC;
+use OC\App\DependencyAnalyzer;
 use OC\App\Platform;
 use OCP\IL10N;
 use Test\TestCase;
@@ -22,11 +22,11 @@ class DependencyAnalyzerTest extends TestCase {
 	/** @var IL10N */
 	private $l10nMock;
 
-	/** @var \OC\App\DependencyAnalyzer */
+	/** @var DependencyAnalyzer */
 	private $analyser;
 
 	public function setUp() {
-		$this->platformMock = $this->getMockBuilder('\OC\App\Platform')
+		$this->platformMock = $this->getMockBuilder(Platform::class)
 			->disableOriginalConstructor()
 			->getMock();
 		$this->platformMock->expects($this->any())
@@ -67,7 +67,7 @@ class DependencyAnalyzerTest extends TestCase {
 				return vsprintf($text, $parameters);
 			}));
 
-		$this->analyser = new \OC\App\DependencyAnalyzer($this->platformMock, $this->l10nMock);
+		$this->analyser = new DependencyAnalyzer($this->platformMock, $this->l10nMock);
 	}
 
 	/**
@@ -101,6 +101,8 @@ class DependencyAnalyzerTest extends TestCase {
 
 	/**
 	 * @dataProvider providesDatabases
+	 * @param $expectedMissing
+	 * @param $databases
 	 */
 	public function testDatabases($expectedMissing, $databases) {
 		$app = [
@@ -247,6 +249,8 @@ class DependencyAnalyzerTest extends TestCase {
 				[['@attributes' => ['min-version' => '2.3', 'max-version' => '2.3'], '@value' => 'curl']]],
 			[[],
 				[['@attributes' => ['min-version' => '2', 'max-version' => '2'], '@value' => 'curl']]],
+			[[],
+				['@attributes' => ['min-version' => '2', 'max-version' => '2'], '@value' => 'curl']],
 		];
 	}