Merge pull request #1381 from matthewhegarty/collect-failed-rows-crash

Fix crash when import_data() called with empty Dataset and collect_failed_rows=True (#1381)

docs/changelog.rst

@@ -4,7 +4,7 @@ Changelog
 2.7.2 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Fix crash when import_data() called with empty Dataset and `collect_failed_rows=True` (#1381)
 
 
 2.7.1 (2021-12-23)

import_export/results.py

@@ -106,6 +106,7 @@ def append_base_error(self, error):
         self.base_errors.append(error)
 
     def add_dataset_headers(self, headers):
+        headers = list() if not headers else headers
         self.failed_dataset.headers = headers + ["Error"]
 
     def append_failed_row(self, row, error):

tests/core/tests/test_resources.py

@@ -469,6 +469,11 @@ def test_import_data_raises_field_specific_validation_errors(self):
         self.assertIs(result.rows[0].import_type, results.RowResult.IMPORT_TYPE_INVALID)
         self.assertIn('birthday', result.invalid_rows[0].field_specific_errors)
 
+    def test_import_data_empty_dataset_with_collect_failed_rows(self):
+        resource = AuthorResource()
+        result = resource.import_data(tablib.Dataset(), collect_failed_rows=True)
+        self.assertEqual(['Error'], result.failed_dataset.headers)
+
     def test_collect_failed_rows(self):
         resource = ProfileResource()
         headers = ['id', 'user']

tests/core/tests/test_results.py

@@ -15,10 +15,20 @@ def setUp(self):
         self.dataset = Dataset(*rows, headers=headers)
 
     def test_add_dataset_headers(self):
+        target = ['some_header', 'Error']
+        self.result.add_dataset_headers(['some_header'])
+        self.assertEqual(target, self.result.failed_dataset.headers)
+
+    def test_add_dataset_headers_empty_list(self):
         target = ['Error']
         self.result.add_dataset_headers([])
         self.assertEqual(target, self.result.failed_dataset.headers)
 
+    def test_add_dataset_headers_None(self):
+        target = ['Error']
+        self.result.add_dataset_headers(None)
+        self.assertEqual(target, self.result.failed_dataset.headers)
+
     def test_result_append_failed_row_with_ValidationError(self):
         target = [[1, 'Some book', "['some error']"]]
         self.result.append_failed_row(self.dataset.dict[0], ValidationError('some error'))