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weakref proxy doesn't support the matrix multiplication operator #80850
Description
| BPO | 36669 |
|---|---|
| Nosy | @freddrake, @mdickinson, @njsmith, @mr-nfamous |
| PRs |
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/mdickinson'
closed_at = <Date 2019-04-26.08:46:22.259>
created_at = <Date 2019-04-19.14:08:57.116>
labels = ['3.8', 'type-feature', 'library']
title = "weakref proxy doesn't support the matrix multiplication operator"
updated_at = <Date 2019-04-26.08:46:22.258>
user = 'https://github.com/mr-nfamous'bugs.python.org fields:
activity = <Date 2019-04-26.08:46:22.258>
actor = 'mark.dickinson'
assignee = 'mark.dickinson'
closed = True
closed_date = <Date 2019-04-26.08:46:22.259>
closer = 'mark.dickinson'
components = ['Library (Lib)']
creation = <Date 2019-04-19.14:08:57.116>
creator = 'bup'
dependencies = []
files = []
hgrepos = []
issue_num = 36669
keywords = ['patch']
message_count = 6.0
messages = ['340553', '340760', '340763', '340767', '340885', '340894']
nosy_count = 5.0
nosy_names = ['fdrake', 'mark.dickinson', 'njs', 'SilentGhost', 'bup']
pr_nums = ['12932']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue36669'
versions = ['Python 3.8']
Activity
SilentGhost commentedon Apr 19, 2019
It's not obvious why it should. Do you care to show a use case you had in mind?
mdickinson commentedon Apr 24, 2019
I'd say that it's not obvious why it shouldn't. The "weakproxy" type currently supports every single "PyNumberMethods" slot *except* matrix multiplication: see
cpython/Objects/weakrefobject.c
Lines 610 to 645 in bf94cc7
It seems likely that this was an unintentional omission when matrix multiplication was added. I can't think of any good reason to support all but one (well, two, including the in-place method) of those PyNumberMethods. Supporting all of them gives a (conceptually) smaller, simpler object.
I think this is a consistency bug that should be fixed.
mdickinson commentedon Apr 24, 2019
Adding Nathaniel Smith (the matrix multiplication PEP author), just in case he knows some reason why weakref.proxy objects should _not_ support the matrix multiplication operator.
njsmith commentedon Apr 24, 2019
Yeah, seems like a simple oversight to me. (Actually this is the first I've heard of weakref.proxy...)
mdickinson commentedon Apr 26, 2019
New changeset 7abb6c0 by Mark Dickinson in branch 'master':
bpo-36669: add matmul support to weakref.proxy (GH-12932)
7abb6c0
mdickinson commentedon Apr 26, 2019
Now fixed for 3.8. Although this was an oversight, I'm erring on the side of regarding this as a new feature for 3.8 (and I think the omission is unlikely to bite anyone for Python 3.7 or 3.6), so I wouldn't recommend backporting this.
Thanks for the report!