See the code example below.

```python
import platform
import pickle

pack = {
    'uname_result': platform.uname()
}

with open('test.pickle', 'wb') as f:
    pickle.dump(pack, f, protocol=pickle.HIGHEST_PROTOCOL)

with open('test.pickle', 'rb') as f:
    data = pickle.load(f)

```

It works smoothly on Python 3.8.5. However, on Python 3.9.0, the last line produces this error:

```
Traceback (most recent call last):
  File "/Users/crocoduck/pickle/3.9.0/make_pickle.py", line 12, in <module>
    data = pickle.load(f)
TypeError: <lambda>() takes 6 positional arguments but 7 were given
```

The files produced by the code snipped above are attached for reference.

This was observed in macOS Catalina 10.15.7.

See also issue42189.

The PR for the related issue does address pickling. Do you expect pickles to work across Python versions?

Hi, I somehow missed the other issue while searching for something 
similar to this, sorry about that.

The main issue is that files pickled with python 3.9.0 cannot be read 
back by using python 3.9.0 if they contain a `uname_result` object.

As for expecting pickle to work across different versions: I did not 
actually think about that. In the original message I mentioned python 
3.8.5 as I noticed this issue did not happen in python 3.8.5, so I 
though it was useful information. To my (hopefully correct) 
understanding if a python version supports the same protocol that was 
used to create the pickle file then it is expected to work. For example 
I have observed that files containing `uname_result` objects pickled 
with python 3.7.6 are still readable with python 3.8.5. As far as I 
understand this is the expected behavior.

On 16/12/2020 22:08, Jason R. Coombs wrote:
> Jason R. Coombs <jaraco@jaraco.com> added the comment:
>
> The PR for the related issue does address pickling. Do you expect pickles to work across Python versions?
>
> ----------
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue42659>
> _______________________________________

New changeset a6fd0f414c0cb4cd5cc20eb2df3340b31c6f7743 by Jason R. Coombs in branch 'master':
bpo-42163, bpo-42189, bpo-42659: Support uname_tuple._replace (for all but processor) (#23010)
https://github.com/python/cpython/commit/a6fd0f414c0cb4cd5cc20eb2df3340b31c6f7743

New changeset 799722cb0ddb90752cde7798cab543f30623ebf2 by Jason R. Coombs in branch '3.9':
[3.9] bpo-42163, bpo-42189, bpo-42659: Support uname_tuple._replace (for all but processor) (GH-23010) (#24232)
https://github.com/python/cpython/commit/799722cb0ddb90752cde7798cab543f30623ebf2