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The ast module fails to reject certain malformed nodes #84535

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The ast module fails to reject certain malformed nodes#84535
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brandtbucher
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3.9 (EOL)end of lifestdlibStandard Library Python modules in the Lib/ directorytype-bugAn unexpected behavior, bug, or error

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@brandtbucher
brandtbucher
opened on Apr 21, 2020
BPO 40355
Nosy @pablogsal, @miss-islington, @remilapeyre, @brandtbucher, @isidentical, @curtisbucher
PRs
  • bpo-40355: ast.literal_eval rejects malformed Dict nodes #19868
  • [3.8] bpo-40355: Improve error messages in ast.literal_eval with malformed Dict nodes (GH-19868) #19947
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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/brandtbucher'
closed_at = <Date 2020-05-06.08:21:23.178>
created_at = <Date 2020-04-21.19:59:22.958>
labels = ['type-bug', 'library', '3.9']
title = 'The ast module fails to reject certain malformed nodes'
updated_at = <Date 2020-05-06.08:21:23.177>
user = 'https://github.com/brandtbucher'

    bugs.python.org fields:

    activity = <Date 2020-05-06.08:21:23.177>
actor = 'BTaskaya'
assignee = 'brandtbucher'
closed = True
closed_date = <Date 2020-05-06.08:21:23.178>
closer = 'BTaskaya'
components = ['Library (Lib)']
creation = <Date 2020-04-21.19:59:22.958>
creator = 'brandtbucher'
dependencies = []
files = []
hgrepos = []
issue_num = 40355
keywords = ['patch']
message_count = 4.0
messages = ['366938', '366941', '368200', '368202']
nosy_count = 6.0
nosy_names = ['pablogsal', 'miss-islington', 'remi.lapeyre', 'brandtbucher', 'BTaskaya', 'curtisbucher']
pr_nums = ['19868', '19947']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40355'
versions = ['Python 3.9']

    Activity

    1. brandtbucher commented on Apr 21, 2020

      @brandtbucher
      brandtbucher
      on Apr 21, 2020
      MemberAuthor

      There are several places in the ast module where the use of zip is allowing malformed nodes to have unpaired children silently thrown away. A couple of short examples:

      >>> from ast import Constant, Dict, literal_eval, unparse
>>> nasty_dict = Dict(keys=[Constant("I don't have a value!")], values=[])
>>> unparse(nasty_dict)
'{}'
>>> literal_eval(nasty_dict)
{}

      I'm currently working on a patch to raise errors instead.

    2. brandtbucher
      added
      3.9 (EOL)end of life
      on Apr 21, 2020
    3. brandtbucher
      self-assigned this
      on Apr 21, 2020
    4. brandtbucher
      added
      stdlibStandard Library Python modules in the Lib/ directory
      type-bugAn unexpected behavior, bug, or error
      3.9 (EOL)end of life
      on Apr 21, 2020
    5. brandtbucher
      self-assigned this
      on Apr 21, 2020
    6. brandtbucher
      added
      stdlibStandard Library Python modules in the Lib/ directory
      type-bugAn unexpected behavior, bug, or error
      on Apr 21, 2020

    7. isidentical commented on Apr 21, 2020

      @isidentical
      isidentical
      on Apr 21, 2020
      SponsorMember

      See https://bugs.python.org/msg360767 for ast.unparse's point of view regarding malformed nodes.

    8. pablogsal commented on May 5, 2020

      @pablogsal
      pablogsal
      on May 5, 2020
      Member

      New changeset c21c512 by Curtis Bucher in branch 'master':
      bpo-40355: Improve error messages in ast.literal_eval with malformed Dict nodes (GH-19868)
      c21c512

    9. miss-islington commented on May 5, 2020

      @miss-islington
      miss-islington
      on May 5, 2020
      Contributor

      New changeset 2a3b876 by Miss Islington (bot) in branch '3.8':
      bpo-40355: Improve error messages in ast.literal_eval with malformed Dict nodes (GH-19868)
      2a3b876

    10. isidentical
      closed this as completedon May 6, 2020
    11. isidentical
      closed this as completedon May 6, 2020
    12. ezio-melotti
      transferred this issue fromon Apr 10, 2022
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