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Integer Overflow in __len__ #56368
Description
| BPO | 12159 |
|---|---|
| Nosy | @vstinner, @benjaminp |
| 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 = None
closed_at = <Date 2011-05-23.14:27:30.522>
created_at = <Date 2011-05-23.14:24:02.217>
labels = ['OS-windows']
title = 'Integer Overflow in __len__'
updated_at = <Date 2020-01-12.09:04:36.073>
user = 'https://bugs.python.org/peterfankhaenel'bugs.python.org fields:
activity = <Date 2020-01-12.09:04:36.073>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2011-05-23.14:27:30.522>
closer = 'benjamin.peterson'
components = ['Windows']
creation = <Date 2011-05-23.14:24:02.217>
creator = 'peter.fankhaenel'
dependencies = []
files = []
hgrepos = []
issue_num = 12159
keywords = []
message_count = 4.0
messages = ['136644', '136645', '136646', '359837']
nosy_count = 3.0
nosy_names = ['vstinner', 'benjamin.peterson', 'peter.fankhaenel']
pr_nums = ['17934']
priority = 'normal'
resolution = 'works for me'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue12159'
versions = ['Python 2.6', 'Python 2.7']
Activity
peterfankhaenel commentedon May 23, 2011
An OverflowError is emitted in case the return value of __len__
exceeds 2**31-1.
The following code:
len (c)
# leads to an OverflowError in the last line. It works flawless for
c.__len__ ()
benjaminp commentedon May 23, 2011
Yep, len() has to return something less than sys.maxsize.
vstinner commentedon May 23, 2011
len(obj) is implemented using PyObject_Size() which is stores the result into a Py_ssize_t, and so is limited to sys.maxsize (2**31-1 or 2**63-1).
This implementation detail should be documented.
vstinner commentedon Jan 12, 2020
New changeset d7c7add by Victor Stinner (Zac Hatfield-Dodds) in branch 'master':
bpo-12159: Document sys.maxsize limit in len() function reference (GH-17934)
d7c7add