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TextIOWrapper assertion failure after read() and SEEK_CUR #70049

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vadmium opened this issue Dec 15, 2015 · 12 comments
Closed

TextIOWrapper assertion failure after read() and SEEK_CUR #70049

vadmium opened this issue Dec 15, 2015 · 12 comments
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@serhiy-storchaka
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3.7 (EOL) end of life 3.8 only security fixes topic-IO type-crash A hard crash of the interpreter, possibly with a core dump

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@vadmium
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vadmium commented Dec 15, 2015

BPO 25862
Nosy @vadmium, @serhiy-storchaka, @ZackerySpytz, @miss-islington
PRs
  • bpo-25862: Fix an assertion failure in io.TextIOWrapper.tell(). #3918
  • [3.7] bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918) #8007
  • [3.6] bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918) #8012
  • [2.7] bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918) #8013
  • bpo-25862: Fix several bugs in the _io module. #8026
  • [3.7] bpo-25862: Fix several bugs in the _io module. (GH-8026) #8028
  • [3.6] bpo-25862: Fix several bugs in the _io module. (GH-8026) #8029
  • [2.7] bpo-25862: Fix several bugs in the _io module. (GH-8026) #8033
    		•

    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/serhiy-storchaka'
closed_at = <Date 2018-12-04.10:47:52.634>
created_at = <Date 2015-12-15.01:43:10.182>
labels = ['3.7', '3.8', 'expert-IO', 'type-crash']
title = 'TextIOWrapper assertion failure after read() and SEEK_CUR'
updated_at = <Date 2019-02-08.23:20:42.391>
user = 'https://github.com/vadmium'

    bugs.python.org fields:

    activity = <Date 2019-02-08.23:20:42.391>
actor = 'martin.panter'
assignee = 'serhiy.storchaka'
closed = True
closed_date = <Date 2018-12-04.10:47:52.634>
closer = 'serhiy.storchaka'
components = ['IO']
creation = <Date 2015-12-15.01:43:10.182>
creator = 'martin.panter'
dependencies = []
files = []
hgrepos = []
issue_num = 25862
keywords = ['patch']
message_count = 12.0
messages = ['256430', '320312', '320709', '320710', '320732', '320737', '320780', '320798', '320802', '320803', '331024', '335118']
nosy_count = 4.0
nosy_names = ['martin.panter', 'serhiy.storchaka', 'ZackerySpytz', 'miss-islington']
pr_nums = ['3918', '8007', '8012', '8013', '8026', '8028', '8029', '8033']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue25862'
versions = ['Python 2.7', 'Python 3.6', 'Python 3.7', 'Python 3.8']
    @vadmium
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    vadmium commented Dec 15, 2015 

    Python 3.5.1+ (3.5:014e6f7d7c1a, Dec 14 2015, 11:20:58) 
[GCC 5.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from io import *
>>> text = TextIOWrapper(BytesIO(b"x"), "ascii")
>>> text.read(1)
'x'
>>> text.read()
''
>>> text.seek(0, SEEK_CUR)
python: ./Modules/_io/textio.c:2293: _io_TextIOWrapper_tell_impl: Assertion `self->decoded_chars == ((void *)0) || PyUnicode_GetLength(self->decoded_chars) == 0' failed.
Aborted (core dumped)
[Exit 134]

    May affect other versions; I haven’t looked.

    @vadmium vadmium added topic-IO type-crash A hard crash of the interpreter, possibly with a core dump labels Dec 15, 2015
    @ZackerySpytz ZackerySpytz mannequin added the 3.7 (EOL) end of life label Nov 7, 2017
    @serhiy-storchaka
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    Similar case:

    text.read(1); text.write(b'x'); text.tell()

    And there may be crashes after setting self->snapshot to NULL due to the failure of Py_BuildValue().

    @serhiy-storchaka
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    New changeset 23db935 by Serhiy Storchaka (Zackery Spytz) in branch 'master':
    bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918)
    23db935

    @miss-islington
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    New changeset eabebbb by Miss Islington (bot) in branch '3.7':
    bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918)
    eabebbb

    @serhiy-storchaka
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    New changeset d6a283b by Serhiy Storchaka (Zackery Spytz) in branch '3.6':
    [3.6] bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918). (GH-8012)
    d6a283b

    @serhiy-storchaka
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    New changeset 0464de0 by Serhiy Storchaka (Zackery Spytz) in branch '2.7':
    [2.7] bpo-25862: Fix assertion failures in io.TextIOWrapper.tell(). (GH-3918). (GH-8013)
    0464de0

    @serhiy-storchaka
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    The assertion failure can be also caused by setting self->snapshot to NULL when Py_BuildValue() fails due to lack of memory. It is very difficult to reproduce this. PR 8026 fixes this and other difficulty reproducible refcount bugs in the _io module.

    @serhiy-storchaka serhiy-storchaka added the 3.8 only security fixes label Jun 30, 2018
    @serhiy-storchaka serhiy-storchaka self-assigned this Jun 30, 2018
    @serhiy-storchaka
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    New changeset fdb5a50 by Serhiy Storchaka in branch 'master':
    bpo-25862: Fix several bugs in the _io module. (GH-8026)
    fdb5a50

    @miss-islington
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    New changeset dedb28e by Miss Islington (bot) in branch '3.7':
    bpo-25862: Fix several bugs in the _io module. (GH-8026)
    dedb28e

    @miss-islington
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    New changeset e5153d0 by Miss Islington (bot) in branch '3.6':
    bpo-25862: Fix several bugs in the _io module. (GH-8026)
    e5153d0

    @serhiy-storchaka
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    New changeset eab421b by Serhiy Storchaka in branch '2.7':
    [2.7] bpo-25862: Fix several bugs in the _io module. (GH-8026) (GH-8033)
    eab421b

    @vadmium
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    vadmium commented Feb 8, 2019

    I haven’t confirmed, but it looks like the original change here broke bidirectional reading and writing with a single TextIOWrapper object; see bpo-35928.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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    3.7 (EOL) end of life 3.8 only security fixes topic-IO type-crash A hard crash of the interpreter, possibly with a core dump
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