On 14 June 2017 at 08:49, Mahmoud Hashemi <mahm...@hatnote.com> wrote: > Oh I know the traceback, I've had many brought to my desk by a confused > junior dev, looking a lot like yours truly a few years back. :)
Something worth noting is that as of 3.7, all circular imports that actually *are* resolvable at runtime will be resolved: https://bugs.python.org/issue30024 However, that only impacts submodules where the submodule entry exists in sys.modules, but the name hasn't been bound in the parent module yet - it doesn't help with module level attributes that would be defined eventually, but we're still too early in the module's import process for them to exist yet. As Chris pointed out, there are two key points of name resolution to take into account for those cases: * ModuleType.__getattr__ ("import a; a.q") * from_list processing in the import system ("from a import q") Since the import system already keeps track of "currently in progress imports" to manage the per-module import locks, both of those could potentially be updated to query _frozen_importlib._module_locks to find out if the source module was currently in the process of being imported and raise a new CircularImportError that inherited from both AttributeError and ImportError when that was the case. 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/
