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math.copysign raises SystemError with non-float x and custom y #84052

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auscompgeek mannequin opened this issue Mar 6, 2020 · 13 comments
Closed

math.copysign raises SystemError with non-float x and custom y #84052

auscompgeek mannequin opened this issue Mar 6, 2020 · 13 comments
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@mdickinson
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3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes easy extension-modules C modules in the Modules dir type-bug An unexpected behavior, bug, or error

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@auscompgeek
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auscompgeek mannequin commented Mar 6, 2020

BPO 39871
Nosy @mdickinson, @methane, @auscompgeek, @ZackerySpytz, @miss-islington
PRs
  • bpo-39871: Fix possible SystemErrors in math.{atan2,copysign,remainder}() #18806
  • [3.8] bpo-39871: Fix possible SystemError in atan2, copysign and remainder (GH-18806) #18989
  • [3.7] bpo-39871: Fix possible SystemError in atan2, copysign and remainder (GH-18806) #18990
  • bpo-39871: Fix an error in a news entry #21749
  • [3.9] bpo-39871: Fix an error in a news entry (GH-21749) #21760
  • [3.8] bpo-39871: Fix an error in a news entry (GH-21749) #22333
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    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 2020-03-14.11:53:04.104>
created_at = <Date 2020-03-06.02:59:01.549>
labels = ['easy', 'type-bug', '3.8', '3.9', 'extension-modules', '3.7']
title = 'math.copysign raises SystemError with non-float x and custom y'
updated_at = <Date 2020-10-26.05:37:20.036>
user = 'https://github.com/auscompgeek'

    bugs.python.org fields:

    activity = <Date 2020-10-26.05:37:20.036>
actor = 'methane'
assignee = 'mark.dickinson'
closed = True
closed_date = <Date 2020-03-14.11:53:04.104>
closer = 'mark.dickinson'
components = ['Extension Modules']
creation = <Date 2020-03-06.02:59:01.549>
creator = 'auscompgeek'
dependencies = []
files = []
hgrepos = []
issue_num = 39871
keywords = ['patch', 'easy (C)']
message_count = 13.0
messages = ['363477', '363492', '363493', '363495', '363496', '363505', '364150', '364152', '364154', '364155', '374975', '374976', '379640']
nosy_count = 5.0
nosy_names = ['mark.dickinson', 'methane', 'auscompgeek', 'ZackerySpytz', 'miss-islington']
pr_nums = ['18806', '18989', '18990', '21749', '21760', '22333']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39871'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']
    @auscompgeek
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    auscompgeek mannequin commented Mar 6, 2020

    If math.copysign(x, y) is passed an x that cannot be converted to a float and a y that implements __float__() in Python, math.copysign() will raise a SystemError from the TypeError resulting from the attempted float conversion of x.

    math.copysign() should probably return immediately if converting the first argument to a float raises an error.

    Example:

    >>> import math
>>> from fractions import Fraction
>>> float(Fraction(-1, 1))  # this is needed to avoid an AttributeError?
-1.0
>>> math.copysign((-1) ** 0.5, Fraction(-1, 1))
TypeError: can't convert complex to float

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.8/numbers.py", line 291, in __float__
    return self.numerator / self.denominator
SystemError: PyEval_EvalFrameEx returned a result with an error set

    @auscompgeek auscompgeek mannequin added extension-modules C modules in the Modules dir type-bug An unexpected behavior, bug, or error labels Mar 6, 2020
    @serhiy-storchaka serhiy-storchaka added easy 3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes labels Mar 6, 2020
    @mdickinson
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    Nice find. This affects not just copysign, but all of the math module functions that use FUNC2 under the hood. (I think that's just "remainder", "atan2" and "copysign".)

    @mdickinson
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    @david: do you have any interest in creating a PR?

    @auscompgeek
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    auscompgeek mannequin commented Mar 6, 2020

    I'm currently rather busy with other work, but if this happens to still be open in a couple of months I might pick it up.

    @mdickinson
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    No problem; I'll likely pick it up (if no-one else does) in the next few days.

    @mdickinson mdickinson self-assigned this Mar 6, 2020
    @ZackerySpytz
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    ZackerySpytz mannequin commented Mar 6, 2020

    I have created a pull request to fix this issue. Please consider taking a look.

    @mdickinson
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    New changeset 5208b4b by Zackery Spytz in branch 'master':
    bpo-39871: Fix possible SystemError in atan2, copysign and remainder (GH-18806)
    5208b4b

    @mdickinson
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    New changeset e634a8a by Mark Dickinson in branch '3.8':
    [3.8] bpo-39871: Fix possible SystemError in atan2, copysign and remainder (GH-18806) (GH-18989)
    e634a8a

    @mdickinson
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    New changeset 4dcfe5f by Mark Dickinson in branch '3.7':
    [3.7] bpo-39871: Fix possible SystemError in atan2, copysign and remainder (GH-18806) (GH-18990)
    4dcfe5f

    @mdickinson
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    Zackery: Thanks for the fix! Now merged and backported to 3.8 and 3.7.

    @methane
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    methane commented Aug 7, 2020

    New changeset 5463635 by Zackery Spytz in branch 'master':
    bpo-39871: Fix an error in a news entry (GH-21749)
    5463635

    @miss-islington
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    New changeset fc354ca by Miss Islington (bot) in branch '3.9':
    bpo-39871: Fix an error in a news entry (GH-21749)
    fc354ca

    @methane
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    methane commented Oct 26, 2020

    New changeset f6255a2 by Zackery Spytz in branch '3.8':
    bpo-39871: Fix an error in a news entry (GH-21749)
    f6255a2

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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