fix #524 check for type list and improve error msg

src/tablib/core.py

@@ -333,9 +333,14 @@ def _set_dict(self, pickle):
             data.dict = [{'age': 90, 'first_name': 'Kenneth', 'last_name': 'Reitz'}]
 
         """
-
+        error_details = "Please check format documentation https://tablib.readthedocs.io/en/stable/formats.html#yaml"
         if not len(pickle):
             return
+
+        if not isinstance(pickle, list):
+            # sometimes pickle is a dict and len(pickle) returns True.
+            # since we access index 0 we should check if the type is list
+            raise UnsupportedFormat(error_details)
 
         # if list of rows
         if isinstance(pickle[0], list):
@@ -350,7 +355,7 @@ def _set_dict(self, pickle):
             for row in pickle:
                 self.append(Row(list(row.values())))
         else:
-            raise UnsupportedFormat
+            raise UnsupportedFormat(error_details)
 
     dict = property(_get_dict, _set_dict)
 

tests/files/issue_524.yaml

@@ -0,0 +1 @@
+title: Voice of Miki Vanoušek

tests/test_tablib.py

@@ -1229,6 +1229,13 @@ def test_yaml_export(self):
         output = self.founders.yaml
         self.assertEqual(output, expected)
 
+    def test_yaml_load(self):
+        """ test issue 524: invalid format  """
+        yaml_source = Path(__file__).parent / 'files' / 'issue_524.yaml'
+        with yaml_source.open(mode='rb') as fh:
+            with self.assertRaises(UnsupportedFormat):
+                tablib.Dataset().load(fh, 'yaml')
+
 
 class LatexTests(BaseTestCase):
     def test_latex_export(self):