[Python-Dev] Tricky way of of creating a generator via a comprehension expression

[Ivan Levkivskyi]

On 22 November 2017 at 20:15, Guido van Rossum <guido at python.org> wrote:

> On Wed, Nov 22, 2017 at 11:08 AM, Ivan Levkivskyi <levkivskyi at gmail.com>
> wrote:
>
>> On 22 November 2017 at 19:54, Jelle Zijlstra <jelle.zijlstra at gmail.com>
>> wrote:
>>
>>>
>>> One proposal is to make it so `g` gets assigned a list, and the `yield`
>>> happens in the enclosing scope (so the enclosing function would have to be
>>> a generator). This was the way things worked in Python 2, I believe.
>>>
>>> Another proposal is to make this code a syntax error, because it's
>>> confusing either way. (For what it's worth, that would be my preference.)
>>>
>>>
>> Concerning this two options it looks like me and Serhiy like the first
>> one, Paul is undecided (), and Antoine is in favor of option 2.
>>
>
> While that may be the right thing to do, it's a silent change in
> semantics, which I find pretty disturbing -- how would people debug such a
> failure?
>

Some may call this just fixing a bug (At least in two mentioned
Stackoverflow questions and in two b.p.o. issues the current behaviour is
considered a bug).
But anyway, it is not me who decides :-)

--
Ivan
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