PyPy support breaking CPython compatibility?

[Ned Batchelder]

On 1/30/18 4:08 PM, Chris Angelico wrote:
> On Wed, Jan 31, 2018 at 7:58 AM, Etienne Robillard<tkadm30 at yandex.com>  wrote:
>> Hi Ned,
>>
>>
>> Le 2018-01-30 à 15:14, Ned Batchelder a écrit :
>>> I'm curious what you had to change for PyPy? (Unless it's a Py2/Py3 thing
>>> as Chris mentions.)
>> Please take a look at the changesets:
>>
>> https://bitbucket.org/tkadm30/libschevo/commits/745d1aeab5c6ee0d336790cf13d16f327e10c2f8
>> https://bitbucket.org/tkadm30/libdurus/commits/875636e9b6caa840fd50ca87d69217d87fc06f43
>>
>> In short, it seems PyPy automagically adds a __weakref__ attribute to
>> __slots__, causing the CPython interpreter to raise a TypeError...
>>
> I'm confused by this:
>
> -if os.environ.get('SCHEVO_OPTIMIZE', '1') == '1':
> +if os.environ.get('SCHEVO_OPTIMIZE', '1') == True:
>
I was also curious about this: when does os.environ.get return anything 
but a string?

--Ned.