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Created on 2004-08-11 08:03 by ncoghlan, last changed 2022-04-11 14:56 by admin. This issue is now closed.
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| File name | Uploaded | Description | Edit | |
| str_join2.diff | ncoghlan, 2004-08-11 22:52 | Fix that preserves optimisation for the two builtin classes | ||
| Messages (8) | |||
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| msg46667 - (view) | Author: Nick Coghlan (ncoghlan) *  |
Date: 2004-08-11 08:03 | |
At present, str.join contains a shortcut that returns a reference to the existing string for a sequence that contains a single item. This can cause misbehaviour when subclasses of str are involved (see the bug report for details). The attached patch removes the shortcut, and adds a test for the correct behaviour. |
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| msg46668 - (view) | Author: Tim Peters (tim.peters) * |
Date: 2004-08-11 12:52 | |
Logged In: YES user_id=31435 This is an important optimization for "true strings". It was indeed the intent that internal optimization for immutable types not be applied to subclass instances, so it's good to fix that. It's not good to lose the optimization when it's safe. |
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| msg46669 - (view) | Author: Nick Coghlan (ncoghlan) * |
Date: 2004-08-11 22:17 | |
Logged In: YES user_id=1038590 OK. I think I can do something with PyString_CheckExact that will do what you'd prefer. |
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| msg46670 - (view) | Author: Nick Coghlan (ncoghlan) * |
Date: 2004-08-11 22:52 | |
Logged In: YES user_id=1038590 New version of patch attached which uses PyString_CheckExact and PyUnicode_CheckExact to determine when the optimisation is safe, and falls through to the general case when it isn't. Should this optimisation be applied to the unicode join as well? |
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| msg46671 - (view) | Author: Nick Coghlan (ncoghlan) * |
Date: 2004-08-11 22:53 | |
Logged In: YES user_id=1038590 Oh - the test looks explicitly for the optimised behaviour for a true string (to make sure this version preserved that behaviour). Is that a good idea, or not? |
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| msg46672 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2004-08-19 22:17 | |
Logged In: YES user_id=80475 The patch looks good, it compiles okay, and the test_suite passes. If Tim has no further issues, I will apply it. |
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| msg46673 - (view) | Author: Tim Peters (tim.peters) * |
Date: 2004-08-19 22:28 | |
Logged In: YES user_id=31435 Unassigned myself -- can't make time for this now. |
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| msg46674 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2004-08-23 23:26 | |
Logged In: YES user_id=80475 Applied as: Objects/stringobject.c 2.225 Lib/test/test_string.py 1.26 Thanks for the perfect patch. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:56:06 | admin | set | github: 40742 |
| 2004-08-11 08:03:32 | ncoghlan | create | |