Yeah, one should never add a module to sys.path that has a __init__.py file.
On Wed, Mar 14, 2018 at 11:25 AM, Brendan Barnwell <brenb...@brenbarn.net> wrote: > On 2018-03-14 04:18, Steven D'Aprano wrote: > >> Apart from intentionally manipulating sys.modules or the import system, >> or playing file system tricks like hard-linking your files, under what >> circumstances can this occur by accident? >> > > It can occur if a given directory winds up appearing twice on the > import path. For instance, if /foo is on the path and /foo/bar is a > package directory with /foo/bar/baz as a subpackage directory, then you can > do "from bar import baz" and "import baz" and wind up with two different > module objects referring to the same module. > > This usually happens when code starts adding paths to sys.path. > This is in some sense "manipulating the import system" but it's something > that a fair number of libraries do in various contexts, in order to be able > to do things like import plugins without requiring the user to make those > plugins available on the default import path. > > For what it's worth, I have been bitten by the problem a few > times, although it's not very common. I think it's worth considering the > proposal, but not sure if any change is justified given that the issue is > fairly obscure. > > -- > Brendan Barnwell > "Do not follow where the path may lead. Go, instead, where there is no > path, and leave a trail." > --author unknown > > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ > -- --Guido van Rossum (python.org/~guido)
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