[issue29025] random.seed() relation to hash() function and its determinism is vague

2016-12-21 Thread Jakub Mateusz Kowalski 

Jakub Mateusz Kowalski added the comment:

Python 2.7
I think note to the docs is enough.

Python 3.5+
I have a doubt. Isn't .seed(a, version=1) still coupled with PYTHONHASHSEED? 
The manual says version 1 is "reproducing random sequences from older versions 
of Python", and for 3.1 (and earlier) hash() is used, which (according to the 
manual) depends on PYTHONHASHSEED. Also, in Python 3.2-3.4 it is stated 
explicitly, that hash() is used.

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[issue29025] random.seed() relation to hash() function and its determinism is vague

2016-12-20 Thread Jakub Mateusz Kowalski 

New submission from Jakub Mateusz Kowalski:

2.7 (https://docs.python.org/2/library/random.html#random.seed)
- warning about PYTHONHASHSEED (environmental variable) voiding determinism
- no warning on -R interpreter switch 
- relation to hash() function omitted

2.6 (https://docs.python.org/2.6/library/random.html#random.seed)
3.0 (https://docs.python.org/3.0/library/random.html#random.seed)
3.1 (https://docs.python.org/3.1/library/random.html#random.seed)
3.2 (https://docs.python.org/3.2/library/random.html#random.seed)
3.3 (https://docs.python.org/3.3/library/random.html#random.seed)
3.4 (https://docs.python.org/3.4/library/random.html#random.seed)
- no warning about PYTHONHASHSEED nor -R switch
- relation to hash() function acknowledged

3.5 (https://docs.python.org/3.5/library/random.html#random.seed)
3.6 (https://docs.python.org/3.6/library/random.html#random.seed)
3.7 (https://docs.python.org/3.7/library/random.html#random.seed)
- no warning about PYTHONHASHSEED nor -R switch
- relation to hash() function omitted

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assignee: docs@python
components: Documentation
messages: 283688
nosy: Jakub.Mateusz.Kowalski, docs@python
priority: normal
severity: normal
status: open
title: random.seed() relation to hash() function and its determinism is vague
versions: Python 2.7, Python 3.3, Python 3.4, Python 3.5, Python 3.6, Python 3.7

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[issue29023] Results of random.seed() call with integer argument should be claimed deterministic.

2016-12-20 Thread Jakub Mateusz Kowalski 

New submission from Jakub Mateusz Kowalski:

In https://docs.python.org/2/library/random.html#random.seed I can find that 
"If a hashable object is given, deterministic results are only assured when 
PYTHONHASHSEED is disabled."

Both int and long are hashable. However, tests on the random module as well as 
C source code of random_seed (as indicated in 
http://stackoverflow.com/a/41228062/4879688) suggest that behaviour of the 
module is deterministic when seeded with an integer.

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assignee: docs@python
components: Documentation
messages: 283686
nosy: Jakub.Mateusz.Kowalski, docs@python
priority: normal
severity: normal
status: open
title: Results of random.seed() call with integer argument should be claimed 
deterministic.
versions: Python 2.7

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[issue24490] DeprecationWarning hidden even after warnings.filterwarnings('always') called

2015-06-23 Thread Jakub Mateusz Kowalski 

New submission from Jakub Mateusz Kowalski:

The error occurs when there was a warning before the call to filterwarnings():

$ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type help, copyright, credits or license for more information.
 import warnings
 warnings.warn('aa', DeprecationWarning)
 warnings.filterwarnings('always')
 warnings.warn('aa', DeprecationWarning)


When filterwarnings() is called before warnings, everything is working as 
expected:

$ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type help, copyright, credits or license for more information.
 import warnings
 warnings.filterwarnings('always')
 warnings.warn('aa', DeprecationWarning)
__main__:1: DeprecationWarning: aa
 warnings.warn('aa', DeprecationWarning)
__main__:1: DeprecationWarning: aa


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components: Interpreter Core
messages: 245691
nosy: Jakub.Mateusz.Kowalski
priority: normal
severity: normal
status: open
title: DeprecationWarning hidden even after warnings.filterwarnings('always') 
called
type: behavior
versions: Python 2.7

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[issue22526] file iteration crashes for huge lines (2GiB+)

2014-09-30 Thread Jakub Mateusz Kowalski 

New submission from Jakub Mateusz Kowalski:

File /tmp/2147483648zeros is 2^31 (2GiB) zero-bytes ('\0').

Readline method works fine:
 fh = open('/tmp/2147483648zeros', 'rb')
 line = fh.readline()
 len(line)
2147483648

However when I try to iterate over the file:
 fh = open('/tmp/2147483648zeros', 'rb')
 for line in fh:
...   print len(line)

SystemError Traceback (most recent call last)
/home/jkowalski/ipython-input-55-aaa9ddb42aea in module()
 1 for line in fh:
  2 print len(line)
  3 
SystemError: Negative size passed to PyString_FromStringAndSize


Same is for greater files (issue discovered for 2243973120 B).
For a shorter file iteration works as expected.


File /tmp/2147483647zeros is 2^31 - 1 ( 2GiB) zero-bytes.
 fh = open('/tmp/2147483647zeros', 'rb')
 for line in fh:
...   print len(line)
2147483647


I guess the variable used for size is of 32bit signed type.

I am using Python 2.7.3 (default, Feb 27 2014, 19:58:35) with IPython 0.12.1 on 
Ubuntu 12.04.5 LTS.

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components: IO
messages: 227949
nosy: Jakub.Mateusz.Kowalski
priority: normal
severity: normal
status: open
title: file iteration crashes for huge lines (2GiB+)
type: crash
versions: Python 2.7

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