MockMemcacheClient should always return str or bytes (?)

[snarfed]

Hi all! Right now, if you set an int or float value in a MockMemcacheClient (with the default serde) and then get it, you get the same native int or float. For parity with production memcached, get should always return these as bytes, right? Eg right now this happens:

>>> mc = MockMemcacheClient()
>>> mc.set('x', 3)
True
>>> mc.get('x')
3

...which doesn't match real memcache:

>>> mc = PooledClient(...)
>>> mc.set('x', 3)
True
>>> mc.get('x')
b'3'

I started on a PR for this in master...snarfed:pymemcache:MockMemcacheClient-get-int-serde , but it's pretty awkward, I kind of doubt it's the right direction.

[GonzaloAvilez]

Hi @snarfed,

Maybe It could be a confusion about how they are implemented in your project.Perhaps, you could check the Client class documentations :py:class:pymemcache.client.base.Client. Client class is used by PooledClient class.
Maybe you can keep an eye in serde argument in the constructor class and compare how you are using/implementing in your project the docs recomend to use a serialization

Maybe here could be your answers

If you intend to use anything but str as a value, it is a good idea to use
a serializer. The pymemcache.serde library has an already implemented
serializer which pickles and unpickles data.

Extra Note:
MockMemcacheClient has its own serde arg; you could implement in your tests and match your tests assertions with the same result in in your get Cache implementation.

I strongly suggest consider the class documentation before to modify the code in the library.

[snarfed]

Hi @GonzaloAvilez! I'm familiar with serde, and I'm actually using a PooledClient in both cases here. (I simplified the repro code above a bit.) I'm also using the default serde in both cases, ie not specifying my own.

I can definitely use an explicit serde to fix this. My point is that for MockMemcacheClient to be useful, it needs to do the exact same thing as real client(s), at least as often as possible. Here, it doesn't.

[snarfed]

I looked into this more, and it looks like the issue is indeed the interaction between PooledClient and MockMemcacheClient.

On its own, MockMemcacheClient faithfully emulates real memcached by encoding str values to bytes, so set('k', 'done') followed by get('k') returns b'done'. This is done via the _serializer closure in MockMemcacheClient.init, which only takes effect when serializer/serde are left as None.

However, PooledClient._create_client always passes its own serde down to each inner client (serde=self.serde), and a PooledClient constructed without an explicit serde defaults to a pure passthrough LegacyWrappingSerde(None, None). That passthrough overrides the mock's encoding serializer, so PooledClient(client_class=MockMemcacheClient).get(...) returns the original str, whereas the real client always returns bytes.

[GonzaloAvilez]

Yes, that's true, i agree with you,

I believe that since this is a Mocked function, with some deprecated code interaction. The most convenient could be document this legacy code somewhere in your codebase proyect within your tests, I dont have idea if there is another current effort to refactor this of fix it.
IMO , since this is a Mock object doesnt impact directly in production envs only keep an eye with the correct asserttions.

But good eye from your side man to detect this.