Fix #54: do deeper lookup for inhereted classes

CHANGES.txt

@@ -6,6 +6,8 @@ CHANGES
 
 * Implement monitoring ZMQ events #50
 
+* Do deeper lookup for inhereted classes #54
+
 0.6.1 (2015-05-19)
 ^^^^^^^^^^^^^^^^^^
 

aiozmq/rpc/packer.py

@@ -25,6 +25,11 @@ def __init__(self, *, translation_table=None):
             translation_table = ChainMap(translation_table, _default)
         self.translation_table = translation_table
         self._pack_cache = {}
+        self._unpack_cache = {}
+        for code in sorted(self.translation_table):
+            cls, packer, unpacker = self.translation_table[code]
+            self._pack_cache[cls] = (code, packer)
+            self._unpack_cache[code] = unpacker
 
     def packb(self, data):
         return packb(data, encoding='utf-8', use_bin_type=True,
@@ -46,6 +51,7 @@ def ext_type_pack_hook(self, obj, _sentinel=object()):
                 cls, packer, unpacker = self.translation_table[code]
                 if isinstance(obj, cls):
                     self._pack_cache[obj_class] = (code, packer)
+                    self._unpack_cache[code] = unpacker
                     return ExtType(code, packer(obj))
             else:
                 self._pack_cache[obj_class] = None
@@ -57,7 +63,7 @@ def ext_type_pack_hook(self, obj, _sentinel=object()):
 
     def ext_type_unpack_hook(self, code, data):
         try:
-            cls, packer, unpacker = self.translation_table[code]
+            unpacker = self._unpack_cache[code]
             return unpacker(data)
         except KeyError:
             return ExtType(code, data)

tests/rpc_packer_test.py

@@ -172,3 +172,24 @@ def test_override_translators(self):
         self.assertEqual(ExtType(125, data), packer.ext_type_pack_hook(pt))
         with self.assertRaisesRegex(TypeError, "Unknown type: "):
             packer.ext_type_pack_hook(dt)
+
+    def test_preserve_resolution_order(self):
+        class A:
+            pass
+
+        class B(A):
+            pass
+
+        dump_a = mock.Mock(return_value=b'a')
+        load_a = mock.Mock(return_value=A())
+
+        dump_b = mock.Mock(return_value=b'b')
+        load_b = mock.Mock(return_value=B())
+
+        translation_table = {
+            1: (A, dump_a, load_a),
+            2: (B, dump_b, load_b),
+        }
+        packer = _Packer(translation_table=translation_table)
+        self.assertEqual(packer.packb(ExtType(1, b'a')), packer.packb(A()))
+        self.assertEqual(packer.packb(ExtType(2, b'b')), packer.packb(B()))