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bpo-38605: Make 'from __future__ import annotations' the default (GH-20434)

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The hard part was making all the tests pass; there are some subtle issues here, because apparently the future import wasn't tested very thoroughly in previous Python versions.

For example, `inspect.signature()` returned type objects normally (except for forward references), but strings with the future import. We changed it to try and return type objects by calling `typing.get_type_hints()`, but fall back on returning strings if that function fails (which it may do if there are future references in the annotations that require passing in a specific namespace to resolve).
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Batuhan Taskaya 2020-10-06 23:03:02 +03:00 • committed by GitHub
parent bef7d299eb
commit 044a1048ca
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27 changed files with 403 additions and 299 deletions
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32
Lib/test/dataclass_module_2_str.py
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@ -1,32 +0,0 @@
from __future__ import annotations
USING_STRINGS = True
# dataclass_module_2.py and dataclass_module_2_str.py are identical
# except only the latter uses string annotations.
from dataclasses import dataclass, InitVar
from typing import ClassVar
T_CV2 = ClassVar[int]
T_CV3 = ClassVar
T_IV2 = InitVar[int]
T_IV3 = InitVar
@dataclass
class CV:
T_CV4 = ClassVar
cv0: ClassVar[int] = 20
cv1: ClassVar = 30
cv2: T_CV2
cv3: T_CV3
not_cv4: T_CV4 # When using string annotations, this field is not recognized as a ClassVar.
@dataclass
class IV:
T_IV4 = InitVar
iv0: InitVar[int]
iv1: InitVar
iv2: T_IV2
iv3: T_IV3
not_iv4: T_IV4 # When using string annotations, this field is not recognized as an InitVar.