Fix murmur2 bug handling python2 bytes that do not ascii encode (#815)

* Add test for murmur2 py2 bytes bug
* Fix murmur2 handling of python2 bytes
* Drop bytearray / str / unicode MurmurPartitioner tests -- no longer supported
* Make DefaultPartitioner importable from kafka.partitioner

kafka/partitioner/__init__.py

@@ -1,9 +1,10 @@
 from __future__ import absolute_import
 
-from .roundrobin import RoundRobinPartitioner
+from .default import DefaultPartitioner
 from .hashed import HashedPartitioner, Murmur2Partitioner, LegacyPartitioner
+from .roundrobin import RoundRobinPartitioner
 
 __all__ = [
-    'RoundRobinPartitioner', 'HashedPartitioner', 'Murmur2Partitioner',
-    'LegacyPartitioner'
+    'DefaultPartitioner', 'RoundRobinPartitioner', 'HashedPartitioner',
+    'Murmur2Partitioner', 'LegacyPartitioner'
 ]

kafka/partitioner/hashed.py

@@ -49,22 +49,20 @@ HashedPartitioner = LegacyPartitioner
 
 
 # https://github.com/apache/kafka/blob/0.8.2/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L244
-def murmur2(key):
+def murmur2(data):
     """Pure-python Murmur2 implementation.
 
     Based on java client, see org.apache.kafka.common.utils.Utils.murmur2
 
     Args:
-        key: if not a bytes type, encoded using default encoding
+        data (bytes): opaque bytes
 
-    Returns: MurmurHash2 of key bytearray
+    Returns: MurmurHash2 of data
     """
-
-    # Convert key to bytes or bytearray
-    if isinstance(key, bytearray) or (six.PY3 and isinstance(key, bytes)):
-        data = key
-    else:
-        data = bytearray(str(key).encode())
+    # Python2 bytes is really a str, causing the bitwise operations below to fail
+    # so convert to bytearray.
+    if six.PY2:
+        data = bytearray(bytes(data))
 
     length = len(data)
     seed = 0x9747b28c

test/test_partitioner.py

@@ -1,9 +1,7 @@
-import pytest
-import six
+from __future__ import absolute_import
 
-from kafka.partitioner import Murmur2Partitioner
-from kafka.partitioner.default import DefaultPartitioner
-from kafka.partitioner import RoundRobinPartitioner
+from kafka.partitioner import DefaultPartitioner, Murmur2Partitioner, RoundRobinPartitioner
+from kafka.partitioner.hashed import murmur2
 
 
 def test_default_partitioner():
@@ -55,16 +53,6 @@ def test_roundrobin_partitioner():
         i += 1
 
 
-def test_hash_bytes():
-    p = Murmur2Partitioner(range(1000))
-    assert p.partition(bytearray(b'test')) == p.partition(b'test')
-    
-
-def test_hash_encoding():
-    p = Murmur2Partitioner(range(1000))
-    assert p.partition('test') == p.partition(u'test')
-
-
 def test_murmur2_java_compatibility():
     p = Murmur2Partitioner(range(1000))
     # compare with output from Kafka's org.apache.kafka.clients.producer.Partitioner
@@ -74,3 +62,9 @@ def test_murmur2_java_compatibility():
     assert p.partition(b'abc') == 107
     assert p.partition(b'123456789') == 566
     assert p.partition(b'\x00 ') == 742
+
+
+def test_murmur2_not_ascii():
+    # Verify no regression of murmur2() bug encoding py2 bytes that dont ascii encode
+    murmur2(b'\xa4')
+    murmur2(b'\x81' * 1000)