Merge remote-tracking branch 'mainline/2.3.3-develop' into MC-15977

Author: eug123

app/code/Magento/ImportExport/Model/Import.php

@@ -568,9 +568,15 @@ public function uploadSource()
         $entity = $this->getEntity();
         /** @var $uploader Uploader */
         $uploader = $this->_uploaderFactory->create(['fileId' => self::FIELD_NAME_SOURCE_FILE]);
+        $uploader->setAllowedExtensions(['csv', 'zip']);
         $uploader->skipDbProcessing(true);
         $fileName = $this->random->getRandomString(32) . '.' . $uploader->getFileExtension();
-        $result = $uploader->save($this->getWorkingDir(), $fileName);
+        try {
+            $result = $uploader->save($this->getWorkingDir(), $fileName);
+        } catch (\Exception $e) {
+            throw new LocalizedException(__('The file cannot be uploaded.'));
+        }
+
         // phpcs:disable Magento2.Functions.DiscouragedFunction.Discouraged
         $extension = pathinfo($result['file'], PATHINFO_EXTENSION);
 

dev/tests/integration/testsuite/Magento/ImportExport/Controller/Adminhtml/Import/ValidateTest.php

@@ -93,7 +93,7 @@ public function validationDataProvider(): array
             [
                 'file_name' => 'test.txt',
                 'mime-type' => 'text/csv',
-                'message' => '\'txt\' file extension is not supported',
+                'message' => 'The file cannot be uploaded.',
                 'delimiter' => ',',
             ],
             [