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Created on2015-05-25 11:41 byserhiy.storchaka, last changed2022-04-11 14:58 byadmin. This issue is nowclosed.
| Files | ||||
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| File name | Uploaded | Description | Edit | |
| str_tailmatch.patch | serhiy.storchaka,2015-05-25 11:41 | review | ||
| Messages (8) | |||
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| msg244027 -(view) | Author: Serhiy Storchaka (serhiy.storchaka)* | Date: 2015-05-25 11:41 | |
The behavior of startswith in corner case is inconsistent between str and bytes in Python 3, str and unicode in Python 2, and between str in Python 2 and Python 3.Python 3:>>> ''.startswith('', 1, 0)True>>> b''.startswith(b'', 1, 0)FalsePython 2:>>> ''.startswith('', 1, 0)False>>> u''.startswith(u'', 1, 0)TrueIf define s1.startswith(s2, start, end) for non-negative indices and non-tuple s2 as an equivalent to the expression `start + len(s2) <= end and s2[start: start + len(s2)] == s2` or to `s1.find(s2, start, end) == start`, "".startswith("", 1, 0) should be False.The same issue exists for endswith. Seeissue24243 for more detailed discussion.Proposed patch fixes str.startswith and str.endswith. | |||
| msg244036 -(view) | Author: R. David Murray (r.david.murray)* | Date: 2015-05-25 14:02 | |
I think this can only be applied in a feature release (and I think it should be, because of the backward-compatibility-with-python2 issue). However, since this is potentially controversial, we need some more opinions. | |||
| msg244068 -(view) | Author: Martin Panter (martin.panter)* | Date: 2015-05-26 00:19 | |
I can’t imagine much code would rely on either old or new behaviour. If you only put it into a feature release, would you have to document it as a change in behaviour? | |||
| msg244106 -(view) | Author: R. David Murray (r.david.murray)* | Date: 2015-05-26 14:43 | |
Just in the what's new porting section, I think. The fact that there "should" be very little to no code that relies on this is why I'd like to see it fixed. The fact that the report was a theoretical one, and not one that broke code, is why I think we should fix it only in 3.5. | |||
| msg244124 -(view) | Author: Serhiy Storchaka (serhiy.storchaka)* | Date: 2015-05-26 18:56 | |
Could you please help me with wording? | |||
| msg244139 -(view) | Author: Martin Panter (martin.panter)* | Date: 2015-05-26 22:14 | |
How about this for What’s New:* The :meth:`str.startswith` and :meth:`str.endswith` methods no longer return ``True`` when finding the empty string and the indexes are completely out of range. See :issue:`24284`.Perhaps that is good enough, but if you wanted to be more precise, I think the actual condition is if the *start* index is beyond the end of the string, or *end* is before *start*. | |||
| msg244520 -(view) | Author: Serhiy Storchaka (serhiy.storchaka)* | Date: 2015-05-31 06:09 | |
Thank you Martin. | |||
| msg244521 -(view) | Author: Roundup Robot (python-dev) | Date: 2015-05-31 06:17 | |
New changeseta82498f424fe by Serhiy Storchaka in branch '3.5':Issue#24284: The startswith and endswith methods of the str class no longerhttps://hg.python.org/cpython/rev/a82498f424feNew changeset04162e06323f by Serhiy Storchaka in branch 'default':Issue#24284: The startswith and endswith methods of the str class no longerhttps://hg.python.org/cpython/rev/04162e06323f | |||
| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:17 | admin | set | github: 68472 |
| 2015-05-31 06:17:31 | serhiy.storchaka | set | status: open -> closed resolution: fixed stage: patch review -> resolved |
| 2015-05-31 06:17:05 | python-dev | set | nosy: +python-dev messages: +msg244521 |
| 2015-05-31 06:09:05 | serhiy.storchaka | set | assignee:serhiy.storchaka messages: +msg244520 versions: + Python 3.6 |
| 2015-05-26 22:14:53 | martin.panter | set | messages: +msg244139 |
| 2015-05-26 18:56:46 | serhiy.storchaka | set | messages: +msg244124 |
| 2015-05-26 14:43:20 | r.david.murray | set | messages: +msg244106 |
| 2015-05-26 00:19:28 | martin.panter | set | nosy: +martin.panter messages: +msg244068 |
| 2015-05-25 22:01:43 | rhettinger | set | nosy: +rhettinger |
| 2015-05-25 14:02:32 | r.david.murray | set | nosy: +r.david.murray messages: +msg244036 versions: - Python 2.7, Python 3.4, Python 3.6 |
| 2015-05-25 11:41:27 | serhiy.storchaka | create | |