Hashable memoryviews

[pitrou]

BPO	13411
Nosy	@ncoghlan, @pitrou, @vstinner, @skrah, @meadori, @ericsnowcurrently
Files	memhash.patch

^{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 = None
closed_at = <Date 2012-01-25.17:44:39.654>
created_at = <Date 2011-11-15.22:20:43.048>
labels = ['interpreter-core', 'type-feature']
title = 'Hashable memoryviews'
updated_at = <Date 2012-01-25.17:44:39.654>
user = 'https://github.com/pitrou'

bugs.python.org fields:

activity = <Date 2012-01-25.17:44:39.654>
actor = 'skrah'
assignee = 'none'
closed = True
closed_date = <Date 2012-01-25.17:44:39.654>
closer = 'skrah'
components = ['Interpreter Core']
creation = <Date 2011-11-15.22:20:43.048>
creator = 'pitrou'
dependencies = []
files = ['23697']
hgrepos = []
issue_num = 13411
keywords = ['patch']
message_count = 10.0
messages = ['147714', '147811', '147812', '147813', '147814', '147815', '148080', '148082', '151451', '151955']
nosy_count = 8.0
nosy_names = ['ncoghlan', 'pitrou', 'vstinner', 'skrah', 'meador.inge', 'neologix', 'python-dev', 'eric.snow']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue13411'
versions = ['Python 3.3']

[pitrou]

This patch allows hashing of memoryviews, as discussed on python-dev.

[vstinner]

Does memory_hash() reject non-contiguous memory?

_Py_HashBytes() might be reused by unicode_hash() for PyUnicode_1BYTE_KIND.

[vstinner]

Except these two minor nits, the patch looks good to me.

[pitrou]

Does memory_hash() reject non-contiguous memory?

It should, since it checks the strides array.

_Py_HashBytes() might be reused by unicode_hash() for PyUnicode_1BYTE_KIND.

I don't really see how unicode hashing should be related to bytes
hashing (even though apparently an (outdated?) test checks for that).

[neologix]

I'm not sure that the "register" storage class specifier is still relevant with modern compilers: I'm pretty sure gcc ignores it unless -O0, and I think I've read somewhere Microsoft's compiler ignores it too.

[pitrou]

I'm not sure that the "register" storage class specifier is still
relevant with modern compilers: I'm pretty sure gcc ignores it unless
-O0, and I think I've read somewhere Microsoft's compiler ignores it
too.

I don't think so either. I was lazily moving the original code, but I
could remove those bits.

[python-dev]

New changeset 215690b782f8 by Antoine Pitrou in branch 'default':
Issue bpo-13411: memoryview objects are now hashable when the underlying object is hashable.
http://hg.python.org/cpython/rev/215690b782f8

[pitrou]

Fixed, thanks.

[skrah]

Reopening as a reminder that it isn't fixed yet in http://hg.python.org/features/pep-3118 .

[skrah]

Done in: http://hg.python.org/features/pep-3118/rev/508d5e3c579c