Since when builtin dict preserve key order?

[Serhiy Storchaka]

24.03.18 10:48, Marko Rauhamaa пише:
> Chris Angelico <rosuav at gmail.com>:
>> On Sat, Mar 24, 2018 at 3:34 PM, Arkadiusz Bulski
>> <arek.bulski at gmail.com> wrote:
>>> I already asked on PYPY and they confirmed that any version of pypy,
>>> including 2.7, has dict preserving insertion order. I am familiar
>>> with ordered **kw which was introduced in 3.6 but I also heard that
>>> builtin dict preserves order since 3.5. Is that true?
>>>
>>
>> I don't think 3.5 had it. According to the tracker, it landed in 3.6:
>>
>> https://bugs.python.org/issue27350
>>
>> But yes, current versions of CPython preserve insertion order.
> 
> Is that part of the Python Language Specification? If not, it shouldn't
> be exploited in application programs.

Only in the future version 3.7. Surprisingly it isn't mentioned in 
"What’s New In Python 3.7" yet.