enlist only registered sections that also have settings registered to

lib/private/Settings/Manager.php

@@ -327,10 +327,6 @@ class Manager implements IManager {
 	 * @inheritdoc
 	 */
 	public function getAdminSections() {
-		$query = $this->dbc->getQueryBuilder();
-		$query->select(['class', 'priority'])
-			->from(self::TABLE_ADMIN_SECTIONS);
-
 		// built-in sections
 		$sections = [
 			 0 => [new Section('server',        $this->l->t('Server settings'), 0)],
@@ -341,7 +337,15 @@ class Manager implements IManager {
 			99 => [new Section('tips-tricks',   $this->l->t('Tips & tricks'), 0)],
 		];
 
+		$query = $this->dbc->getQueryBuilder();
+		$query->selectDistinct('s.class')
+			->addSelect('s.priority')
+			->from(self::TABLE_ADMIN_SECTIONS, 's')
+			->from(self::TABLE_ADMIN_SETTINGS, 'f')
+			->where($query->expr()->eq('s.id', 'f.section'))
+		;
 		$result = $query->execute();
+
 		while($row = $result->fetch()) {
 			if(!isset($sections[$row['priority']])) {
 				$sections[$row['priority']] = [];

tests/lib/Settings/ManagerTest.php

@@ -136,15 +136,33 @@ class ManagerTest extends TestCase {
 
 	public function testGetAdminSections() {
 		$qb = $this->getMockBuilder('\OCP\DB\QueryBuilder\IQueryBuilder')->getMock();
+		$expr = $this->getMockBuilder('OCP\DB\QueryBuilder\IExpressionBuilder')->getMock();
 		$qb
 			->expects($this->once())
 			->method('select')
-			->with(['class', 'priority'])
+			->with(['s.class', 's.priority'])
+			->willReturn($qb);
+		$qb
+			->expects($this->exactly(2))
+			->method('from')
+			->willReturn($qb);
+		$qb
+			->expects($this->at(1))
+			->method('from')
+			->with('admin_sections', 's')
+			->willReturn($qb);
+		$qb
+			->expects($this->at(2))
+			->method('from')
+			->with('admin_settings', 'f')
 			->willReturn($qb);
 		$qb
 			->expects($this->once())
-			->method('from')
-			->with('admin_sections')
+			->method('expr')
+			->willReturn($expr);
+		$qb
+			->expects($this->once())
+			->method('where')
 			->willReturn($qb);
 		$stmt = $this->getMockBuilder('\Doctrine\DBAL\Driver\Statement')->getMock();
 		$qb