Support imports of namespaces in python>=3.3 (modules without __init__.py files)

[mishas]

Python 3.3 introduced "Implicit Namespace Packages" (based on PEP-420), which states the following:
"Native support for package directories that don’t require __init__.py marker files [...]".

In other words, if I have the following file structure (without any __init__.py files whatsoever):

foo/
    bar/
        baz.py
blah.py

And the content of blah.py is from foo.bar import baz; print(baz), then python3.5 ./blah.py will successfully output: <module 'foo.bar.baz' from '/tmp/foo/bar/baz.py'>.

The problem is, that pylint ./blah.py outputs:
E: 1, 0: Unable to import 'foo.bar' (import-error)

I tried to manipulate sys.path (from init-hook of my .pylintrc) in any which way, and nothing seemed to help except for adding the __init__.py files everywhere :(.

[PCManticore]

Agree that this would be nice to have, but not sure when this will happen.

[srikanth-viswanathan]

This would be great to have. Is this just a minor enhancement? Out of curiosity, where would the change have to be made?

[kstrauser]

For my organization, it's not minor but a real showstopper. We use lots of namespace packages and are moving to the new implicit namespace package layout, so we can't use pylint in the mean time. Is this something a motivated would-be contributor with no prior pylint experience could reasonably fix?

[moylop260]

@kstrauser
I had a similar issue with import check but I can use pylint with pylint... --disable=import-error
FYI You can try it to use pylint with other checks that works but disabling the checks that don't work for you

[kstrauser]

@moylop260 But I use import errors. :-/ I've temporarily switched to flake8 but I'd much prefer pylint on the CI server.

[moylop260]

Flake8 don't have import-error is the same if you use pylint disabling it
But is a good choice too!

[moylop260]

A big problem with use import-error in the CI is that many times you need a speed-up result of lint checks, but for this check (and just this check) you will need install all depends, then could be slower the result of this build.

[PCManticore]

@kstrauser, this would probably be a bit difficult, since it will require modifications through astroid as well (the inference engine of Pylint). But if you want to tackle it, I can help you with the details.

[kstrauser]

@PCManticore Thanks, after looking at it that might be outside my current resource availability. I'm going to keep that in mind as a possibility, though.

[PCManticore]

Let's fix this before the next release. I'm assigning to me for now, but if anyone wants to chime in and help, I wouldn't mind.

[PCManticore]

For the record, I started implementing this feature. It's pretty much work in progress, but you can check these two branches https://github.com/PyCQA/pylint/commits/namespace_package and https://github.com/PyCQA/astroid/commits/namespace_package. It doesn't support Python 3.3 though, it is a bit cumbersome to support it, but if someone needs it, say it now.

[PCManticore]

This should be fixed, you'll need the pylint's and astroid's master branch if you want to test. Please give it a go and let me know if you have problems with it.

[moylop260]

@PCManticore
FYI the build is red of the change 38a56db
IMHO we should avoid use push directly without a pull request

[cblegare]

This is closed but I don't think it was merged. Any news ?

[PCManticore]

This is available in the master branch. It will be released though in a
couple of months, since we have some more work to do. You can check the
milestone page to see what's blocking us so far.

On Aug 2, 2016 8:06 PM, "abstrus" [email protected] wrote:

This is closed but I don't think it was merged. Any news ?

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[janosh]

This is available in the master branch. It will be released though in a couple of months, ...

I'm still having this problem? Was the release ever published?

[PCManticore]

This was already released @janosh but there might be some bugs lurking around. Please open a new issue with some reproduction examples.

[janosh]

Never mind, I was specifying the imports from the wrong starting point, i.e. from package import module rather than from src.package import module. Working now.

[webknjaz]

FTR this error pops up for me with the latest pylint under Python 3.7 but occasionally: only in Travis CI and GitHub Actions CI/CD. No errors locally. I've been trying to figure out the difference between envs but still no luck...