The __new__ method should suffice, and having both interferes with providing
a __new__ in namedtuples, which we want to do to fix
https://github.com/python/mypy/issues/1279.
memoryview type information inconsistent with documentation of typing module.
`memoryview` should be a ByteString like the docs say.
`memoryview.__init__` does not accept str, and instead of a union it should just accept ByteString.
`memoryview.__iter__` returns an Iterator[int] not bytes.
This commit reorders any overloads where the first overload was
"shadowing" the second, preventing it from ever being matched by type
checkers that work by selecting the first matching overload alternative.
For example, the first overload alternative below is strictly broader
then the second, preventing it from ever being selected:
class Parent: pass
class Child(Parent): pass
@overload
def foo(x: *int) -> Parent: ...
@overload
def foo(x: int, y: int) -> Child: ...
The correct thing to do is to either delete the second overload or
rearrange them to look like this:
@overload
def foo(x: int, y: int) -> Child: ...
@overload
def foo(x: *int) -> Parent: ...
Rationale: I'm currently [working on a proposal][0] that would amend
PEP 484 to (a) mandate type checkers check overloads in order and
(b) prohibit overloads where an earlier alternative completely shadows
a later one.
[0]: https://github.com/python/typing/issues/253#issuecomment-389262904
This would prohibit overloads that look like the example below, where
the first alternative completely shadows the second.
I figured it would be a good idea to make these changes ahead of time:
if my proposal is accepted, it'd make the transition smoother. If not,
this is hopefully a relatively harmless change.
Note: I think some of these overloads could be simplified (e.g.
`reversed(...)`), but I mostly stuck with rearranging them in case I was
wrong. The only overload I actually changed was `hmac.compare_digest` --
I believe the Python 2 version actually accepts unicode.
In Python 3, the ndigits argument of round() defaults to None. If
ndigits is excluded or explicitly None, the result is always an int. If
ndigits is not None, the result should be the same type as the number.
$ cat test.py
from fractions import Fraction
print(type(round(0.1)))
print(type(round(0.1, None)))
print(type(round(0.1, 0)))
print(type(round(Fraction(1, 10))))
print(type(round(Fraction(1, 10), None)))
print(type(round(Fraction(1, 10), 0)))
$ python3 ./test.py
<class 'int'>
<class 'int'>
<class 'float'>
<class 'int'>
<class 'int'>
<class 'fractions.Fraction'>
Update the signatures to allow for an ndigits of None.
- Made deque.maxlen read-only
- We don't support 3.2, so we don't care about signature changes in it
- There don't seem to be any missing set operations (I compared the dir() of this class to that of builtins.set)
str.translate requires a Mapping or Sequence (in essence, anything
with __getitem__), not a Dict.
str.maketrans in the one-argument form only converts character string
keys to their unicode ordinal, leaving any of the values untouched.
This mapping may use both integers or strings as keys at the same time.
str.maketrans in the multi-argument form returns a dict with any of the
values str, int or None, as recognized by str.translate.
In Python 3 (but not Python 2), `object().__dir__()` works and returns a list of strings.
This is relevant when implementing a custom `__dir__` that invokes `super().__dir__()`.
* Update default values to `...` in `__init__` and `__new__` in `int` and `str`.
* Add `__new__` to `enum.IntEnum` to override inherited `__new__`.
* Add `type: ignore` comment to `IntEnum`
From Samuel Freilich:
In Python 2, the predicate parameter in itertools.ifilter and
itertools.ifilterfalse can be None, indicating that true or false values
should be retained (functionally equivalent to passing "bool" as the
predicate). In Python 3, filter and itertools.filterfalse have
the same behavior.
