Allow an Item to be created without a hash/range key to handle situat…

…ion where attributes_to_get does not include hash/range. Fixes boto#656.

boto/dynamodb/item.py

@@ -41,15 +41,8 @@ def __init__(self, table, hash_key=None, range_key=None, attrs=None):
         self._updates = None
         self._hash_key_name = self.table.schema.hash_key_name
         self._range_key_name = self.table.schema.range_key_name
-        if hash_key is None:
-            if attrs.get(self._hash_key_name) is None:
-                raise DynamoDBItemError('You must supply a hash_key')
-            hash_key = attrs[self._hash_key_name]
-        if self._range_key_name:
-            if range_key is None:
-                if attrs.get(self._range_key_name) is None:
-                    raise DynamoDBItemError('You must supply a range_key')
-                range_key = attrs[self._range_key_name]
+        hash_key = hash_key or attrs.get(self._hash_key_name, None)
+        range_key = range_key or attrs.get(self._range_key_name, None)
         self[self._hash_key_name] = hash_key
         if self._range_key_name:
             self[self._range_key_name] = range_key

tests/dynamodb/test_layer2.py

@@ -102,13 +102,6 @@ def test_layer2_basic(self):
             'LastPostDateTime':  '12/9/2011 11:36:03 PM'}
 
         # Test a few corner cases with new_item
-        # First, try not supplying a hash_key
-        self.assertRaises(DynamoDBItemError,
-                          table.new_item, None, item1_range, item1_attrs)
-
-        # Try supplying a hash but no range
-        self.assertRaises(DynamoDBItemError,
-                          table.new_item, item1_key, None, item1_attrs)
 
         # Try supplying a hash_key as an arg and as an item in attrs
         item1_attrs[hash_key_name] = 'foo'