fix hashing

[tmick]

BPO	400503
Nosy	@gvanrossum, @tim-one, @freddrake
Files	None: None

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/freddrake'
closed_at = <Date 2000-06-29.19:20:34.000>
created_at = <Date 2000-06-06.02:40:44.000>
labels = []
title = 'fix hashing'
updated_at = <Date 2000-06-29.19:20:34.000>
user = 'https://bugs.python.org/tmick'

bugs.python.org fields:

activity = <Date 2000-06-29.19:20:34.000>
actor = 'fdrake'
assignee = 'fdrake'
closed = True
closed_date = None
closer = None
components = ['None']
creation = <Date 2000-06-06.02:40:44.000>
creator = 'tmick'
dependencies = []
files = ['2435']
hgrepos = []
issue_num = 400503
keywords = ['patch']
message_count = 8.0
messages = ['32676', '32677', '32678', '32679', '32680', '32681', '32682', '32683']
nosy_count = 4.0
nosy_names = ['gvanrossum', 'tim.peters', 'fdrake', 'tmick']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue400503'
versions = []

[tmick]

No description provided.

[tmick]

This patch addresses two main issues:
(1) There exist some non-fatal errors in some of the hash algorithms. For
exmaple, in float_hash and complex_hash a certain part of the value is
not included in the hash calculation. See Tim's, Guido's, and my
discussion of this on python-dev in May under the title
"fix float_hash and complex_hash for 64-bit *nix"

(2) The hash algorithms that use pointers (e.g. func_hash, code_hash) are
universally not correct on Win64 (they assume that sizeof(long) ==
sizeof(void*))

As well, this patch significantly cleans up the hash code. It adds the two
function _Py_HashDouble and _PyHash_VoidPtr that the various hashing routine
are changed to use.

These help maintain the hash function invariant:
(a==b) => (hash(a)==hash(b)))
I have added Lib/test/test_hash.py and Lib/test/output/test_hash to test this
for some cases.

[tmick]

I confirm that, to the best of my knowledge and belief, this
contribution is free of any claims of third parties under
copyright, patent or other rights or interests ("claims"). To
the extent that I have any such claims, I hereby grant to CNRI a
nonexclusive, irrevocable, royalty-free, worldwide license to
reproduce, distribute, perform and/or display publicly, prepare
derivative versions, and otherwise use this contribution as part
of the Python software and its related documentation, or any
derivative versions thereof, at no cost to CNRI or its licensed
users, and to authorize others to do so.

I acknowledge that CNRI may, at its sole discretion, decide
whether or not to incorporate this contribution in the Python
software and its related documentation. I further grant CNRI
permission to use my name and other identifying information
provided to CNRI by me for use in connection with the Python
software and its related documentation.

[gvanrossum]

just testing the SF patch manager

[gvanrossum]

Tim, please review! Then assign to Trent if it's OK to commit.

[tim-one]

Changed to Accepted, assigned back to Trent for commit.

Looks good, Trent! My only gripe is about the hash function for complex numbers (because it's symmetric), but that problem existed before and you haven't made it any worse. Ship it (I'll improve the complex hash later).

[tim-one]

Changed to Accepted, assigned back to Trent for commit.

Looks good, Trent! My only gripe is about the hash function for complex numbers (because it's symmetric), but that problem existed before and you haven't made it any worse. Ship it (I'll improve the complex hash later).

[freddrake]

Applied verbatim; patch to PC/winreg.c applied to PC/_winreg.c due to name change.