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[Python-Dev] What does a double coding cookie mean?

MRAB python at mrabarnett.plus.com
Tue Mar 15 17:23:33 EDT 2016 
On 2016-03-15 20:53, MRAB wrote:
> On 2016-03-15 20:30, Guido van Rossum wrote:
>> I came across a file that had two different coding cookies -- one on
>> the first line and one on the second. CPython uses the first, but mypy
>> happens to use the second. I couldn't find anything in the spec or
>> docs ruling out the second interpretation. Does anyone have a
>> suggestion (apart from following CPython)?
>>
>> Reference: https://github.com/python/mypy/issues/1281
>>
> I think it should follow CPython.
>
> As I see it, CPython allows it to be on the second line because the
> first line might be needed for the shebang.
>
> If the first two lines both had an encoding, and then you inserted a
> shebang line, the second one would be ignored anyway.
>
A further thought: is mypy just assuming that the first line contains 
the shebang?

If there's only one encoding line, and it's the first line, does mypy 
still get it right?
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