bpo-41026: Path-like object support for mailbox module

[loz-hurst]

Added support for Path-like objects (i.e. pathlib.Path) to mailbox.

https://bugs.python.org/issue41026

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[remilapeyre]

Thanks for this change @loz-hurst ! It looks good, could you add tests for this feature?

[loz-hurst]

Thanks for this change @loz-hurst ! It looks good, could you add tests for this feature?

Certainly, I'm on leave from work next week so I'll sort this out then.

I am also going to do the other half of the work and migrate the os.foo calls to use pathlib where appropriate.

[loz-hurst]

I have reworked mailbox to migrate is to pathlib (where appropriate). Tests have also been migrated/updated as appropriate and additional test to verify construction with a string path (the current behaviour) correctly initialises the Path internally. New behaviour is inherently tested by the migration of the test suite to pathlib.

There's quite a few PEP8 issues with this module, I've corrected most (I need to check naming conventions) in a separate branch in my fork. I'm not sure what the policy is on this - would you accept a new issue & MR to make the module PEP8 compliant or prefer it is just left as-is? As discussed on BPO, this is a very old module and code, and I do not intend to offend anyone by offering to correct the style.

[remilapeyre]

Hi @loz-hurst, I'm sorry but I wish you add kept the approach you took first. The goal is just to make sure that mailbox can accept a Path object as input, not to update its internal code as this makes the change much larger without benefits and it can introduce bugs.

[loz-hurst]

Hi @loz-hurst, I'm sorry but I wish you add kept the approach you took first. The goal is just to make sure that mailbox can accept a Path object as input, not to update its internal code as this makes the change much larger without benefits and it can introduce bugs.

I thought it would be better to migrate to the new way of doing things, while the module was getting a bit of TLC. I presume that there will not be two ways of doing all the things that pathlib now does forever (going against PEP 20's "There should be one-- and preferably only one --obvious way to do it.") and fixing it now for the foreseeable future, as has happened in other modules looking at the change history, is surely a good thing?

In my mind this bug and change was always "update mailbox to use pathlib".