Merge branch 'master' of github.com:web2py/web2py

gluon/storage.py

@@ -275,7 +275,7 @@ class List(list):
     instead of `IndexOutOfBounds`.
     """
 
-    def __call__(self, i, default=None, cast=None, otherwise=None):
+    def __call__(self, i, default=DEFAULT, cast=None, otherwise=None):
         """Allows to use a special syntax for fast-check of `request.args()`
         validity
         Args:
@@ -291,7 +291,9 @@ class List(list):
                 request.args(0,default=0,cast=int,otherwise='http://error_url')
                 request.args(0,default=0,cast=int,otherwise=lambda:...)
         """
-        value = self[i] or default
+        value = self[i]
+        if not value and default is not DEFAULT:
+            value, cast, otherwise = default, False, False
         try:
             if cast:
                 value = cast(value)

gluon/tests/test_storage.py

@@ -138,6 +138,9 @@ class TestList(unittest.TestCase):
         self.assertEqual(a(3, cast=int), 1234)
         a.append('x')
         self.assertRaises(HTTP, a, 4, cast=int)
+        b = List()
+        self.assertEqual(b(0, cast=int, default=None), None)
+        self.assertEqual(b(0, cast=int, default=None, otherwise='something'), None)
 
 
 if __name__ == '__main__':