Created on 2012-07-03 15:08 by William.Schwartz, last changed 2019-11-12 15:04 by alclarks.
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| File name | Uploaded | Description | Edit | |
| test_metaclass.py | William.Schwartz, 2012-07-03 15:30 | Test to demonstrate implicit staticmethodness of __prepare__ | ||
| issue15243_diff_python3.5_3.6_v1.diff | jaysinh.shukla, 2016-06-17 11:04 | review | ||
| Pull Requests | |||
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| URL | Status | Linked | Edit |
| PR 17124 | open | alclarks, 2019-11-12 14:59 | |
| Messages (10) | |||
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| msg164606 - (view) | Author: William Schwartz (William.Schwartz) | Date: 2012-07-03 15:08 | |
Section 3.3.3.2. "Preparing the class namespace" of the documentation (http://docs.python.org/dev/reference/datamodel.html#preparing-the-class-namespace) states that "If the metaclass has a __prepare__ attribute, it is called as ``namespace = metaclass.__prepare__(name, bases, **kwds)``...." This isn't quite true. By just defining a ``__prepare__`` method in a metaclass, the interpreter calls it as it would a static method -- there is no implicit first argument referring to ``metaclass`` as the documentation implies. The documentation should be amended to say that users can decorate ``__prepare__`` as a class method to get ``metaclass`` passed in as the implicit first argument. |
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| msg164607 - (view) | Author: William Schwartz (William.Schwartz) | Date: 2012-07-03 15:30 | |
Attached a unittest script to demonstrate that __prepare__ is implicitly a staticmethod. |
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| msg164685 - (view) | Author: Daniel Urban (daniel.urban) *  |
Date: 2012-07-05 16:47 | |
__prepare__ is not implicitly a staticmethod, and it is called exactly as documented (also in types.prepare_class). There is no implicit first argument because the method is called on the (meta)class object. |
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| msg164696 - (view) | Author: William Schwartz (William.Schwartz) | Date: 2012-07-05 19:59 | |
Daniel, Good point. However it would still be useful for documentation to point out that __prepare__ can be passed the metaclass as the implicit first argument by being decorated by classmethod. I'll post a small patch when I get a chance to add a sentence saying as much in the documentation and reorganize the test cases in Lib/test/test_metaclass.py to make it part of the narrative of the doctests. |
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| msg164697 - (view) | Author: Daniel Urban (daniel.urban) * |
Date: 2012-07-05 20:52 | |
Actually the docs contained a similar sentence ("If the metaclass has a :meth:`__prepare__` attribute (usually implemented as a class or static method), ..."), but it was removed in befd56673c80 when Nick rewrote this section.
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| msg221871 - (view) | Author: Mark Lawrence (BreamoreBoy) * | Date: 2014-06-29 18:08 | |
Does the documentation need amending, yes or no? |
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| msg267459 - (view) | Author: Jelle Zijlstra (Jelle Zijlstra) * |
Date: 2016-06-05 19:00 | |
I think the current documentation is correct and doesn't need changes. There is also already an example of a working __prepare__ method. |
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| msg268356 - (view) | Author: Berker Peksag (berker.peksag) *  |
Date: 2016-06-12 09:51 | |
The documentation should mention that the __prepare__ method must be implemented as a classmethod (see msg164697 for the reference.) The example at https://docs.python.org/dev/reference/datamodel.html#metaclass-example needs to be linked from the "Preparing the class namespace" section. |
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| msg268719 - (view) | Author: Jaysinh shukla (jaysinh.shukla) * | Date: 2016-06-17 11:04 | |
Submitting patch according to this (http://bugs.python.org/issue15243#msg268356) message. Thanks! |
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| msg355470 - (view) | Author: Benjamin Edwards (benedwards14) * | Date: 2019-10-27 15:06 | |
Is this still open, does the patch still need a pull request? |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2019-11-12 15:04:07 | alclarks | set | nosy:
+ alclarks |
| 2019-11-12 14:59:58 | alclarks | set | stage: needs patch -> patch review pull_requests: + pull_request16632 |
| 2019-11-04 16:53:25 | brandtbucher | set | nosy:
+ brandtbucher |
| 2019-10-27 15:06:42 | benedwards14 | set | nosy:
+ benedwards14 messages: + msg355470 |
| 2016-06-17 11:04:37 | jaysinh.shukla | set | files:
+ issue15243_diff_python3.5_3.6_v1.diff nosy: + jaysinh.shukla messages: + msg268719 keywords: + patch |
| 2016-06-12 09:51:54 | berker.peksag | set | nosy:
+ berker.peksag messages: + msg268356 |
| 2016-06-05 19:00:54 | Jelle Zijlstra | set | nosy:
+ Jelle Zijlstra messages: + msg267459 |
| 2016-06-03 08:54:58 | BreamoreBoy | set | nosy:
- BreamoreBoy |
| 2016-06-03 04:22:56 | berker.peksag | set | keywords:
+ easy versions: + Python 3.6, - Python 3.4 |
| 2016-06-03 04:21:51 | berker.peksag | link | issue17352 superseder |
| 2014-06-29 18:08:31 | BreamoreBoy | set | versions:
+ Python 3.4, Python 3.5, - Python 3.2, Python 3.3 nosy: + BreamoreBoy messages: + msg221871 components: - Tests |
| 2012-07-05 20:52:19 | daniel.urban | set | messages: + msg164697 |
| 2012-07-05 19:59:06 | William.Schwartz | set | messages: + msg164696 |
| 2012-07-05 16:47:07 | daniel.urban | set | messages: + msg164685 |
| 2012-07-05 16:35:52 | eric.araujo | set | nosy:
+ ncoghlan, eric.araujo stage: needs patch versions: + Python 3.2 |
| 2012-07-03 17:25:37 | daniel.urban | set | nosy:
+ daniel.urban |
| 2012-07-03 15:30:12 | William.Schwartz | set | files:
+ test_metaclass.py messages: + msg164607 |
| 2012-07-03 15:08:37 | William.Schwartz | create | |