unittest assertSequenceEqual can lead to Difflib.compare() crashing on mostly different sequences

Open
#65,452 8 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
38/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
testing-qa

Research direction

Start by reproducing the failure described in diff_bug34.py through unittest.assertSequenceEqual and inspect the related difflib.compare() behavior. Identify the existing unittest and difflib tests covering sequence comparison, then add coverage for the mostly different sequences so the crash is prevented and the regression is verified.

Written by the indexing model from the issue text.

Description

3.7 (EOL) 3.8 (EOL) stdlib type-bug
BPO 21253
Nosy @tim-one, @terryjreedy, @gpshead, @bitdancer, @jftuga, @nnja, @ilevkivskyi
Files
  • diff_bug34.py
    		•

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

    Show more details

    GitHub fields:

    assignee = None
closed_at = None
created_at = <Date 2014-04-16.15:54:46.162>
labels = ['3.7', '3.8', 'type-bug', 'library']
title = 'unittest assertSequenceEqual can lead to Difflib.compare() crashing on mostly different sequences'
updated_at = <Date 2019-03-08.15:56:27.847>
user = 'https://github.com/nnja'

    bugs.python.org fields:

    activity = <Date 2019-03-08.15:56:27.847>
actor = 'Ernesto Eduardo Medina N\xc3\xba\xc3\xb1ez'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2014-04-16.15:54:46.162>
creator = 'nnja'
dependencies = []
files = ['34911']
hgrepos = []
issue_num = 21253
keywords = []
message_count = 7.0
messages = ['216479', '216809', '216816', '216830', '216835', '248905', '337498']
nosy_count = 8.0
nosy_names = ['tim.peters', 'terry.reedy', 'gregory.p.smith', 'r.david.murray', 'jftuga', 'nnja', 'levkivskyi', 'Ernesto Eduardo Medina N\xc3\xba\xc3\xb1ez']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue21253'
versions = ['Python 2.7', 'Python 3.6', 'Python 3.7', 'Python 3.8']

    Dominant language
    Python
    Stars
    77.2k
    Forks
    36k
    Avg merge
    1d 9h
    Merged PRs (30d)
    558

    Contributor guide

    Open the contributing guide

    First steps

    1. Read the whole issue, then the project's contributing guide.
    2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
    3. Fork the repository and make your change on a branch.
    4. Open a pull request that references the issue number.

    More from python/cpython

    All issues in python/cpython

    Similar issues

    More Python issues

    Get new issues in your inbox

    A short digest of beginner-friendly GitHub issues.