[Debichem-devel] Bug#1023972: Python 3.11 for bookworm?

[Andrius Merkys]

Hi Simon,

On 2023-01-07 13:24, Simon McVittie wrote:
> On Sat, 07 Jan 2023 at 10:23:19 +0200, Andrius Merkys wrote:
>> If I may, I would as well be grateful if someone could give a look at:
>>
>> #1023972 [src:python-ase] FTBFS with Python 3.11 due to
>> pathlib.Path.__enter__() deprecation
>>
>> I have no idea how to fix this and the upstream is silent.
> My first thought on seeing this was: why were Path objects a context
> manager in the first place? What would that mean?
> 
> Looking at the code in python3.10 and python3.11 pathlib, it seems the
> reason this is deprecated is indeed that it didn't make sense:
> 
>      def __enter__(self):
>          # In previous versions of pathlib, __exit__() marked this path as
>          # closed; subsequent attempts to perform I/O would raise an IOError.
>          # This functionality was never documented, and had the effect of
>          # making Path objects mutable, contrary to PEP 428.
>          # In Python 3.9 __exit__() was made a no-op.
>          # In Python 3.11 __enter__() began emitting DeprecationWarning.
>          # In Python 3.13 __enter__() and __exit__() should be removed.
>          warnings.warn("pathlib.Path.__enter__() is deprecated and scheduled "
>                        "for removal in Python 3.13; Path objects as a context "
>                        "manager is a no-op",
>                        DeprecationWarning, stacklevel=2)
>          return self
> 
>      def __exit__(self, t, v, tb):
>          pass
> 
> So the solution seems to be that if your package contains this:
> 
>      with some_path_object:
>          do_stuff(some_path_object)
> 
> replace it with:
> 
>      do_stuff(some_path_object)
> 
> and if it contains:
> 
>      with Path(...) as my_path:
>          do_stuff(my_path)
> 
> replace with:
> 
>      my_path = Path(...)
>      do_stuff(my_path)
> 
> I hope that should be a relatively straightforward change.

Thanks a lot for the hint, this indeed worked. Failure in __enter__() 
threw me off tracks, but now I recall how it is related to 'with' 
construction.

Best wishes,
Andrius