On 19 June 2017 at 04:47, Mahmoud Hashemi <mahm...@hatnote.com> wrote: > Barry, that kind of circular import is actually fine in many (if not most) > cases. Modules are immediately created and importable, thenincrementally > populated. The problem arises when you try to do something with contents of > the module that have not been populated, usually manifesting in the > AttributeError above. > > If you'd like to test this yourself, I've made a tiny demo with a little bit > of documentation: > https://gist.github.com/mahmoud/32fd056a3d4d1cd03a4e8aeff6b5ee70 > > Long story short, circular imports can be a code smell, but they're by no > means universally an error condition. :)
Indeed, and this is why we've been begrudgingly giving ground and ensuring that the cases that *can* be made to work actually succeed in practice. We'll let code linters complain about those cycles, rather than having the interpreter continue to get confused :) However, permitting resolvable circular imports means that for the remaining cases that are genuinely irresolvably broken, any custom detection logic needs to live in some combination of the module attribute lookup code and the IMPORT_FROM opcode implementation, rather than being able to isolate the changes to the import machinery itself. Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
