| msg317852 - (view) |
Author: Oleg Oleinik (Oleg.Oleinik) |
Date: 2018-05-28 14:22 |
| I write file test.py: def __getattr__(key): return None help(__name__) when I try to run it I've got error: Traceback (most recent call last): File "test.py", line 5, in help(__name__) File "C:\Program Files\Python37\lib\_sitebuiltins.py", line 103, in __call__ return pydoc.help(*args, **kwds) File "C:\Program Files\Python37\lib\pydoc.py", line 1894, in __call__ self.help(request) File "C:\Program Files\Python37\lib\pydoc.py", line 1944, in help elif request: doc(request, 'Help on %s:', output=self._output) File "C:\Program Files\Python37\lib\pydoc.py", line 1674, in doc pager(render_doc(thing, title, forceload)) File "C:\Program Files\Python37\lib\pydoc.py", line 1667, in render_doc return title % desc + '\n\n' + renderer.document(object, name) File "C:\Program Files\Python37\lib\pydoc.py", line 385, in document if inspect.ismodule(object): return self.docmodule(*args) File "C:\Program Files\Python37\lib\pydoc.py", line 1136, in docmodule for key, value in inspect.getmembers(object, inspect.isclass): File "C:\Program Files\Python37\lib\inspect.py", line 330, in getmembers for base in object.__bases__: TypeError: 'NoneType' object is not iterable If I change definition of __getattr__ function to: def __getattr__(key): raise AttributeError() then help function runs without errors. But I need to return None value from __getattr__ function. When I wrote this function in class definition there is also no errors during runtime |
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| msg318335 - (view) |
Author: Ivan Levkivskyi (levkivskyi) *  |
Date: 2018-05-31 17:58 |
| Hm, replacing the return with a random string, this leads to another crash: Traceback (most recent call last): File "", line 1, in File "/Users/ilevkivskyi/src/cpython/Lib/_sitebuiltins.py", line 103, in __call__ return pydoc.help(*args, **kwds) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 1895, in __call__ self.help(request) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 1954, in help else: doc(request, 'Help on %s:', output=self._output) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 1674, in doc pager(render_doc(thing, title, forceload)) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 1667, in render_doc return title % desc + '\n\n' + renderer.document(object, name) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 385, in document if inspect.ismodule(object): return self.docmodule(*args) File "/Users/ilevkivskyi/src/cpython/Lib/pydoc.py", line 1157, in docmodule for importer, modname, ispkg in pkgutil.iter_modules(object.__path__): File "/Users/ilevkivskyi/src/cpython/Lib/pkgutil.py", line 123, in iter_modules raise ValueError("path must be None or list of paths to look for " ValueError: path must be None or list of paths to look for modules in The reason is that `__getattr__` is also triggered when a special attribute is looked up. I am not sure what to do with this. This is a bit inconsistent with how classes behave, where e.g. `__len__` is never searched on an instance. But modules are special in many other ways, so maybe we can just fix pydoc (and other tools like inspect) to expect some ill-typed values in special module attributes and fail gracefully? |
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| msg318336 - (view) |
Author: Ivan Levkivskyi (levkivskyi) * |
Date: 2018-05-31 18:01 |
| Adding Yury as an inspect expert. I don't think this is something urgent, we can probably postpone this to 3.7.1. |
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| msg321653 - (view) |
Author: Dong-hee Na (corona10) * |
Date: 2018-07-14 15:04 |
| This script works well on Python2 but not on Python3. I've submitted a PR. Please take a look. |
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| msg321654 - (view) |
Author: Dong-hee Na (corona10) * |
Date: 2018-07-14 15:57 |
| I've checked both cases are now working on my patch. |
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| msg348838 - (view) |
Author: Dong-hee Na (corona10) * |
Date: 2019-08-01 05:15 |
| I close PR 8284. If there is a chance to work with this issue. Please let me know Thanks! |
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