[Python-Dev] Timing for removing legacy Unicode APIs deprecated by PEP 393

[INADA Naoki]

>
> I suppose that many users will start porting to Python 3 only in 2020, after
> 2.7 EOL. After that time we shouldn't support compatibility with 2.7 and can
> start emitting deprecation warnings at runtime. After 1 or 2 releases after
> that we can make corresponding public API always failing and remove private
> API and data fields.
>

Python 3.8 is planned to be released at  2019-10-20.  It's just before 2.7 EOL.
My current thought is:

* In 3.8, we make sure deprecated API emits warning (compile time if possible,
  runtime for others).

* If the deprecation is adopted smoothly, drop them in 3.9 (Mid 2021).
Otherwise,
  removal is postponed to 3.10 (Late 2023).

>
> There are other functions which expect that data is aligned to sizeof(long)
> or 8 bytes.
>
> Siphash hashing is special because it is called not just for strings and
> bytes, but for memoryview, which doesn't guarantee any alignment.
>

Oh, I'm sad about hear that...

> Note that after removing the wchar_t* field the gap will not gone, because
> the size of the structure should be a multiple of the alignment of the first
> field (which is a pointer).

Of course, we need hack for packing.

-- 
INADA Naoki  <songofacandy at gmail.com>