New submission from Gregory Szorc <gregory.sz...@gmail.com>:
(Rereporting from https://github.com/indygreg/PyOxidizer/issues/317.) $ mkdir foo $ cat > foo/__init__.py <<EOF > test = True > EOF $ cat > foo/bar.py <<EOF > from .__init__ import test > EOF $ python3.9 Python 3.9.0 (default, Nov 1 2020, 22:40:00) [GCC 10.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import foo.bar >>> import sys >>> sys.modules['foo'] <module 'foo' from '/home/gps/tmp/pyinit-test/foo/__init__.py'> >>> sys.modules['foo.__init__'] <module 'foo.__init__' from '/home/gps/tmp/pyinit-test/foo/__init__.py'> I am surprised that `from .__init__` even works, as `__init__` isn't a valid module name. What appears to be happening is the path based importer doesn't recognize the `__init__` as special and it falls back to its regular file probing technique to locate a module derive from the path. It finds the `__init__.py[c]` file and imports it. A consequence of this is that the explicit `__init__` import/module exists as a separate module object under `sys.modules`. So you can effectively have the same file imported as 2 module objects living under 2 names. This could of course result in subtle software bugs, like module-level variables not updating when you expect them to. (This could also be a feature for code relying on this behavior, of course.) I only attempted to reproduce with 3.9. But this behavior has likely existed for years. ---------- components: Interpreter Core messages: 382464 nosy: indygreg priority: normal severity: normal status: open title: "from .__init__ import ..." syntax imports a duplicate module type: behavior versions: Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue42564> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
