diff options
| -rw-r--r-- | Doc/library/random.rst | 10 | ||||
| -rw-r--r-- | Doc/whatsnew/3.9.rst | 6 | ||||
| -rw-r--r-- | Lib/random.py | 15 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2019-08-22-01-49-05.bpo-32554.4xiXyM.rst | 1 |
4 files changed, 30 insertions, 2 deletions
diff --git a/Doc/library/random.rst b/Doc/library/random.rst index 90b8624..1bd1856 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -86,6 +86,11 @@ Bookkeeping functions .. versionchanged:: 3.2 Moved to the version 2 scheme which uses all of the bits in a string seed. + .. deprecated:: 3.9 + In the future, the *seed* must be one of the following types: + *NoneType*, :class:`int`, :class:`float`, :class:`str`, + :class:`bytes`, or :class:`bytearray`. + .. function:: getstate() Return an object capturing the current internal state of the generator. This @@ -316,6 +321,11 @@ Alternative Generator Class that implements the default pseudo-random number generator used by the :mod:`random` module. + .. deprecated:: 3.9 + In the future, the *seed* must be one of the following types: + :class:`NoneType`, :class:`int`, :class:`float`, :class:`str`, + :class:`bytes`, or :class:`bytearray`. + .. class:: SystemRandom([seed]) Class that uses the :func:`os.urandom` function for generating random numbers diff --git a/Doc/whatsnew/3.9.rst b/Doc/whatsnew/3.9.rst index 6615a2e..05a17a5 100644 --- a/Doc/whatsnew/3.9.rst +++ b/Doc/whatsnew/3.9.rst @@ -169,6 +169,12 @@ Deprecated of Python. For the majority of use cases users can leverage the Abstract Syntax Tree (AST) generation and compilation stage, using the :mod:`ast` module. +* The :mod:`random` module currently accepts any hashable type as a + possible seed value. Unfortunately, some of those types are not + guaranteed to have a deterministic hash value. After Python 3.9, + the module will restrict its seeds to *None*, :class:`int`, + :class:`float`, :class:`str`, :class:`bytes`, and :class:`bytearray`. + Removed ======= diff --git a/Lib/random.py b/Lib/random.py index 365a019..be4401c 100644 --- a/Lib/random.py +++ b/Lib/random.py @@ -121,7 +121,10 @@ class Random(_random.Random): break def seed(self, a=None, version=2): - """Initialize internal state from hashable object. + """Initialize internal state from a seed. + + The only supported seed types are None, int, float, + str, bytes, and bytearray. None or no argument seeds from current time or from an operating system specific randomness source if available. @@ -143,12 +146,20 @@ class Random(_random.Random): x ^= len(a) a = -2 if x == -1 else x - if version == 2 and isinstance(a, (str, bytes, bytearray)): + elif version == 2 and isinstance(a, (str, bytes, bytearray)): if isinstance(a, str): a = a.encode() a += _sha512(a).digest() a = int.from_bytes(a, 'big') + elif not isinstance(a, (type(None), int, float, str, bytes, bytearray)): + _warn('Seeding based on hashing is deprecated\n' + 'since Python 3.9 and will be removed in a subsequent ' + 'version. The only \n' + 'supported seed types are: None, ' + 'int, float, str, bytes, and bytearray.', + DeprecationWarning, 2) + super().seed(a) self.gauss_next = None diff --git a/Misc/NEWS.d/next/Library/2019-08-22-01-49-05.bpo-32554.4xiXyM.rst b/Misc/NEWS.d/next/Library/2019-08-22-01-49-05.bpo-32554.4xiXyM.rst new file mode 100644 index 0000000..752cf48 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-08-22-01-49-05.bpo-32554.4xiXyM.rst @@ -0,0 +1 @@ +Deprecate having random.seed() call hash on arbitrary types. |