Fix bug whereby __init__ methods with local variables did not have th…

…eir values extracted properly

zounds/persistence/test_util.py

@@ -1,5 +1,5 @@
 import unittest2
-from util import decode_timedelta
+from util import decode_timedelta, extract_init_args
 from zounds.timeseries import Seconds
 
 
@@ -8,3 +8,20 @@ def test_already_decoded_instance_is_returned(self):
         td = Seconds(10)
         decoded = decode_timedelta(td)
         self.assertEqual(td, decoded)
+
+
+class ExtractInitArgsTests(unittest2.TestCase):
+    def test_should_not_include_locals(self):
+        class Blah(object):
+            def __init__(self, x, y):
+                super(Blah, self).__init__()
+                self.x = x
+                z = 10
+                self.y = y + z
+
+        b = Blah(20, 30)
+        args = extract_init_args(b)
+        self.assertEqual(2, len(args))
+        self.assertIn(20, args)
+        self.assertIn(40, args)
+        self.assertNotIn(10, args)

zounds/persistence/util.py

@@ -1,6 +1,7 @@
 import base64
 import re
 import numpy as np
+import inspect
 
 TIMEDELTA_DTYPE_RE = re.compile(r'\[(?P<dtype>[^\]]+)\]')
 
@@ -28,5 +29,5 @@ def extract_init_args(instance):
     cls = instance.__class__
     args = filter(
         lambda x: x != 'self',
-        cls.__init__.im_func.func_code.co_varnames)
+        inspect.getargspec(cls.__init__).args)
     return [instance.__dict__[key] for key in args]