Return default from hash client when using positional argument (#354)

When using HashClient with ignore_exc, get would always return
None if no server is available and the default is passed as a
positional argument. The other clients return the default
value in this case. An earlier fix only had the desired effect when
passing default as a keyword argument.

For example, Django passes the default as a positional argument.

Return the default value so HashClient behaves like the other
clients.

ChangeLog.rst

@@ -1,6 +1,11 @@
 Changelog
 =========
 
+Unreleased
+----------
+* ``Client.get`` returns the default when using ``ignore_exc`` and if memcached
+  is unavailable
+
 New in version 3.5.0
 --------------------
 * Sockets are now closed on ``MemcacheUnexpectedCloseError``.

pymemcache/client/hash.py

@@ -356,9 +356,8 @@ def close(self):
     def set(self, key, *args, **kwargs):
         return self._run_cmd('set', key, False, *args, **kwargs)
 
-    def get(self, key, *args, **kwargs):
-        default = kwargs.get('default', None)
-        return self._run_cmd('get', key, default, *args, **kwargs)
+    def get(self, key, default=None, **kwargs):
+        return self._run_cmd('get', key, default, default=default, **kwargs)
 
     def incr(self, key, *args, **kwargs):
         return self._run_cmd('incr', key, False, *args, **kwargs)

pymemcache/test/test_client_hash.py

@@ -262,6 +262,19 @@ def test_no_servers_left_with_commands_return_default_value(self):
         result = client.set('foo', 'bar')
         assert result is False
 
+    def test_no_servers_left_return_positional_default(self):
+        from pymemcache.client.hash import HashClient
+        client = HashClient(
+            [], use_pooling=True,
+            ignore_exc=True,
+            timeout=1, connect_timeout=1
+        )
+
+        # Ensure compatibility with clients that pass the default as a
+        # positional argument
+        result = client.get('foo', 'default')
+        assert result == 'default'
+
     def test_no_servers_left_with_set_many(self):
         from pymemcache.client.hash import HashClient
         client = HashClient(
@@ -381,7 +394,7 @@ def test_dead_server_comes_back(self, client_patch):
         # Client gets removed because of socket timeout
         assert ("127.0.0.1", 11211) in client._dead_clients
 
-        test_client.get.side_effect = lambda *_: "Some value"
+        test_client.get.side_effect = lambda *_, **_kw: "Some value"
         # Client should be retried and brought back
         assert client.get(b"key") == "Some value"
         assert ("127.0.0.1", 11211) not in client._dead_clients
@@ -400,7 +413,7 @@ def test_failed_is_retried(self, client_patch):
         with pytest.raises(socket.timeout):
             client.get(b"key", noreply=False)
 
-        test_client.get.side_effect = lambda *_: "Some value"
+        test_client.get.side_effect = lambda *_, **_kw: "Some value"
         assert client.get(b"key") == "Some value"
 
         assert client_patch.call_count == 1