Fix some nullable methods.

app/Api/V1/Controllers/Controller.php

@@ -61,7 +61,7 @@ abstract class Controller extends BaseController
      *
      * @return string
      */
-    protected function buildParams(): string
+    final protected function buildParams(): string
     {
         $return = '?';
         $params = [];
@@ -83,7 +83,7 @@ abstract class Controller extends BaseController
     /**
      * @return Manager
      */
-    protected function getManager(): Manager
+    final protected function getManager(): Manager
     {
         // create some objects:
         $manager = new Manager;

app/Api/V1/Controllers/RecurrenceController.php

@@ -238,7 +238,7 @@ class RecurrenceController extends Controller
             $result = $recurring->fire();
         } catch (FireflyException $e) {
             Log::error($e->getMessage());
-            throw new FireflyException('200022: Error in cron job.');
+            throw new FireflyException('200022: Error in cron job.',0, $e);
         }
         if (false === $result) {
             return response()->json([], 204);

app/Api/V1/Requests/RecurrenceUpdateRequest.php

@@ -157,16 +157,16 @@ class RecurrenceUpdateRequest extends FormRequest
     /**
      * Returns the repetition data as it is found in the submitted data.
      *
-     * @return array|null
+     * @return array
      */
-    private function getRepetitionData(): ?array
+    private function getRepetitionData(): array
     {
         $return = [];
         // repetition data:
         /** @var array $repetitions */
         $repetitions = $this->get('repetitions');
         if (null === $repetitions) {
-            return null;
+            return [];
         }
         /** @var array $repetition */
         foreach ($repetitions as $repetition) {
@@ -185,16 +185,16 @@ class RecurrenceUpdateRequest extends FormRequest
      * Returns the transaction data as it is found in the submitted data. It's a complex method according to code
      * standards but it just has a lot of ??-statements because of the fields that may or may not exist.
      *
-     * @return array|null
+     * @return array
      */
-    private function getTransactionData(): ?array
+    private function getTransactionData(): array
     {
         $return = [];
         // transaction data:
         /** @var array $transactions */
         $transactions = $this->get('transactions');
         if (null === $transactions) {
-            return null;
+            return [];
         }
         /** @var array $transaction */
         foreach ($transactions as $transaction) {