RFC: rename `PyString` -> `PyStr`, and `PyLong` -> `PyInt`

[davidhewitt]

We currently have PyString to represent Python str, and PyLong to represent Python int.

While PyString is reasonably clear, PyLong is primarily a historical accident based on the fact that Python 2's integers were split between int and long types, and so the Python C API is based on PyLongObject etc.

Interestingly, we do currently expose PyInt as pyo3::types::PyInt as an import alias.

Similar history applies to PyString; we currently have a PyUnicode type alias kicking around which is again a throwback to Python 2's str and unicode split (they became approximately bytes and str respectively in Python 3).

I would propose the following:

• Rename PyString to PyStr, and leave PyString and PyUnicode as deprecated type aliases for a couple versions.
• Similarly rename PyLong to PyInt, and leave PyLong as a deprecated type alias for a couple versions.

The only counter-arguments I can see:

• PyString -> PyStr is not worth the churn. I could accept this if people hold this strongly, though I also think such a migration is a straightforward find-and-replace and improves alignment with the Python naming.
• PyLong -> PyInt is unappealing because we build upon PyLong_ C APIs. After some consideration I find this a non-argument; PyInt is a much clearer name in my opinion, and I don't think we would ever consider PyUnicode as better than PyStr or PyString. So by extension I see no reason to prefer C-API consistency of PyLong over PyInt.

Subject to agreement from maintainers that we want to make this change, I think this is a relatively easy change to implement, so tentatively marking as "Good First Issue".

[LilyFoote]

Makes sense to me!

[Stargateur]

for me PyString make sense cause it's allocate.

[davidhewitt]

for me PyString make sense cause it's allocate.

I do like this argument tbh; and if we chose to leave PyString as-is and just update PyLong -> PyInt, this argument would be a somewhat reasonable justification (alongside the benefit of avoiding churn).

[Icxolu]

I also think PyString is fine as is. PyStr can also make the impression that is would somehow be coupled to Rust's &str, which it is not really. Renaming PyLong to PyInt sounds reasonable to me, given that long is neither a thing in Rust or Python, and PyInt makes is clearer what it refers to.

[davidhewitt]

It sounds like the conclusion here is PyString will stay as-is (we can deprecate the PyUnicode alias, I think, though).

On the other hand, we have broad agreement that PyLong -> PyInt is desirable.

Just need someone to find a moment implement, in that case 👍

[shreyash2002]

Hi @davidhewitt I would love to do changes for PyLong -> PyInt.

I'm still a beginner in rust & open-source. So, this issue would be a good starting point for me

[davidhewitt]

Please feel free to go for it! I suggest starting with a PR and we can review and help iterate that way.