Fixed import error message

CHANGELOG.md

@@ -4,6 +4,9 @@
 ### Changed
 - Improved log messages of failed sendouts ([#138](https://github.com/putyourlightson/craft-campaign/issues/138)).
 
+### Changed
+- Improved the error message when trying to import a CSV file without selecting a mailing list ([#141](https://github.com/putyourlightson/craft-campaign/issues/141)).
+
 ## 1.15.3 - 2020-05-12
 ### Fixed
 - Fixed a bug in the Amazon SES webhook for bounce and complaint notifications ([#103](https://github.com/putyourlightson/craft-campaign/issues/103)).

src/controllers/ImportsController.php

@@ -310,12 +310,12 @@ public function actionDeleteImport(): Response
      * Returns the fields template
      *
      * @param ImportModel $import
-     * @param array $mailingListIds
+     * @param array|string|null $mailingListIds
      *
      * @return Response
      * @throws InvalidConfigException
      */
-    private function _returnFieldsTemplate(ImportModel $import, array $mailingListIds = []): Response
+    private function _returnFieldsTemplate(ImportModel $import, $mailingListIds): Response
     {
         $variables = [];
         $variables['import'] = $import;
@@ -337,11 +337,13 @@ private function _returnFieldsTemplate(ImportModel $import, array $mailingListId
         // Get mailing lists
         $variables['mailingLists'] = [];
 
-        foreach ($mailingListIds as $mailingListId) {
-            $mailingList = Campaign::$plugin->mailingLists->getMailingListById($mailingListId);
+        if (is_array($mailingListIds)) {
+            foreach ($mailingListIds as $mailingListId) {
+                $mailingList = Campaign::$plugin->mailingLists->getMailingListById($mailingListId);
 
-            if ($mailingList !== null) {
-                $variables['mailingLists'][] = $mailingList;
+                if ($mailingList !== null) {
+                    $variables['mailingLists'][] = $mailingList;
+                }
             }
         }