Stub for time.gmtime() looks incorrect

[jolaf]

The following code:

from time import gmtime
(a, b, c, d, e, f, g, h, i) = gmtime()
print(a, b, c, d, e, f, g, h, i)

produces the following output:

$ python3 Test.py 
2019 9 30 16 29 49 0 273 0
$ mypy Test.py
Test.py:3: error: Too many values to unpack (9 expected, 11 provided)

$ mypy --version
mypy 0.730
$ python3 --version
Python 3.6.8

reveal_type(gmtime) produces the following output:
Revealed type is 'def (secs: Union[builtins.float, None] =) -> Tuple[builtins.int, builtins.int, builtins.int, builtins.int, builtins.int, builtins.int, builtins.int, builtins.int, builtins.int, builtins.str, builtins.int, fallback=time.struct_time]

[jolaf]

First reported as python/mypy#7588.

[gvanrossum]

This is painful.

The implementation in Python produces a magical object that unpacks as a 9-tuple but has two additional fields (tm_zone, tm_gmtoff) that are only accessible by name. I'm not even sure how to express that in a typing stub.

The best I can think of is to make a class that inherits from a NamedTuple with 9 fields and then adds the two additional fields. Something like

class N(NamedTuple):
    tm_year: int
    # etc
class struct_tm(N):
    tm_zone: str
    tm_gmtoff: int

But pick a better name than N and handle the version-specific code in time.pyi.

PR welcome!

[JelleZijlstra]

I think we can add the additional fields with @property.