This doesn't really solve the problem imo. Imported symbols shouldn't be i portable elsewhere. Not by import * or explicitly. That's the problem.
One could propose to fix this by doing: 1. Imported symbols and locally declared symbols are put in two different dicts 2. Deprecation warning when you import a symbol from the import dict of another module 3. At some future point promote this to an error In this future re-exporting a symbol might be done with: from foo import bar bar = bar There are other details like being able to programmatically access the import dict for example. I'm +1 on this. > On 26 Jul 2019, at 19:43, Serhiy Storchaka <storch...@gmail.com> wrote: > > From the description of the import statement in the language reference [1]: > >> The *public names* defined by a module are determined by checking the >> module's >> namespace for a variable named ``__all__``; if defined, it must be a sequence >> of strings which are names defined or imported by that module. The names >> given in ``__all__`` are all considered public and are required to exist. If >> ``__all__`` is not defined, the set of public names includes all names found >> in the module's namespace which do not begin with an underscore character >> (``'_'``). ``__all__`` should contain the entire public API. It is intended >> to avoid accidentally exporting items that are not part of the API (such as >> library modules which were imported and used within the module). > > As an example of names which should be excluded from the public API the > reference mentions names of modules which were imported and used within the > module. And they are perhaps the most common cases. It is often imported > module names are the only non-underscored names which are imported by a > star-import by accident. > > For example, modules re and sys were used in Lib/idlelib/editor.py but there > were no imports for them. This worked because they were imported implicitly > by `from tkinter import *`. [1] > > There is other case when a module name can be occurred in the module > namespace: if it is a submodule. For example: > > >>> from xml.etree import * > >>> ElementTree > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > NameError: name 'ElementTree' is not defined > >>> ElementPath > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > NameError: name 'ElementPath' is not defined > >>> import xml.etree.ElementTree > >>> from xml.etree import * > >>> ElementTree > <module 'xml.etree.ElementTree' from > '/home/serhiy/py/cpython3.8/Lib/xml/etree/ElementTree.py'> > >>> ElementPath > <module 'xml.etree.ElementPath' from > '/home/serhiy/py/cpython3.8/Lib/xml/etree/ElementPath.py'> > > Names imported by a `from xml.etree import *` are depended on importing a > xml.etree's submodule ElementTree. I do not think this is good. > > I propose to change the rule for determining the set of public names if > `__all__` is not defined. In addition to underscored names I propose to > exclude names of modules. > > In these rare cases where modules should be imported in a star import it is > not difficult to introduce `__all__`. > > [1] https://docs.python.org/3/reference/simple_stmts.html#the-import-statement > [2] https://bugs.python.org/issue29446 > > _______________________________________________ > Python-ideas mailing list -- python-ideas@python.org > To unsubscribe send an email to python-ideas-le...@python.org > https://mail.python.org/mailman3/lists/python-ideas.python.org/ > Message archived at > https://mail.python.org/archives/list/python-ideas@python.org/message/AKWL7CRCCFACSITAH2NNFBL5BGRKLKJD/ > Code of Conduct: http://python.org/psf/codeofconduct/ _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/UPARIKB6LKNCROYUMDZSTP6BFLDOUF5V/ Code of Conduct: http://python.org/psf/codeofconduct/
