Issue 12159: Integer Overflow in __len__
Issue12159
Created on 2011-05-23 14:24 by peter.fankhaenel, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 17934 | merged | Zac Hatfield-Dodds, 2020-01-10 12:13 | |
| Messages (4) | |||
|---|---|---|---|
| msg136644 - (view) | Author: Peter Fankhaenel (peter.fankhaenel) | Date: 2011-05-23 14:24 | |
An OverflowError is emitted in case the return value of __len__
exceeds 2**31-1.
The following code:
class C (object):
def __len__ (self):
return self.l
c = C()
c.l = 2**31
len (c)
# leads to an OverflowError in the last line. It works flawless for
c.__len__ ()
|
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| msg136645 - (view) | Author: Benjamin Peterson (benjamin.peterson) *  |
Date: 2011-05-23 14:27 | |
Yep, len() has to return something less than sys.maxsize. |
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| msg136646 - (view) | Author: STINNER Victor (vstinner) * |
Date: 2011-05-23 14:30 | |
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. |
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| msg359837 - (view) | Author: STINNER Victor (vstinner) * |
Date: 2020-01-12 09:04 | |
New changeset d7c7adde003ddca5cbe4fc47cf09464ab95a066e by Victor Stinner (Zac Hatfield-Dodds) in branch 'master': bpo-12159: Document sys.maxsize limit in len() function reference (GH-17934) https://github.com/python/cpython/commit/d7c7adde003ddca5cbe4fc47cf09464ab95a066e |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:17 | admin | set | github: 56368 |
| 2020-01-12 09:04:36 | vstinner | set | messages: + msg359837 |
| 2020-01-10 12:13:54 | Zac Hatfield-Dodds | set | pull_requests: + pull_request17339 |
| 2011-05-23 14:30:42 | vstinner | set | nosy:
+ vstinner messages: + msg136646 |
| 2011-05-23 14:27:30 | benjamin.peterson | set | status: open -> closed nosy:
+ benjamin.peterson resolution: works for me |
| 2011-05-23 14:24:02 | peter.fankhaenel | create | |