Missing sub-module import statement is not detected

[pylint-bot]

Originally reported by: Andrew Carman (BitBucket: carmandrew, GitHub: @carmandrew?)

---

When you run pylint on the following file, it reports no errors, but there is very clearly an error when running (AttributeError: 'module' object has no attribute 'saxutils').

import xml.sax.handler

print(xml.sax.handler)
print(xml.sax.saxutils)

---

• Bitbucket: https://bitbucket.org/logilab/pylint/issue/5

[pylint-bot]

Original comment by Andrew Carman (BitBucket: carmandrew, GitHub: @carmandrew?):

---

This example doesn't fail, but it seems like it should still report that you're not explicitly importing the module you need:

import os.path

print(os.name)

[pylint-bot]

Original comment by Sylvain Thénault (BitBucket: sthenault, GitHub: @sthenault?):

---

see http://www.logilab.org/ticket/6646 from the historic tracker

[pylint-bot]

Original comment by Sylvain Thénault (BitBucket: sthenault, GitHub: @sthenault?):

---

@carmandrew I fail to see why a warning should be issued in your os.path/os.name case.

#!python

import os.path

add os to the namespace, so everything is fine. Beside if you don't use os.path anywhere, in which case you're right that a warning would be worth it.

This deserves another ticket though.

[pylint-bot]

Original comment by Andrew Carman (BitBucket: carmandrew, GitHub: @carmandrew?):

---

Yea, you're right about the os path/name example.

[gyermolenko]

I tried to run pylint 1.9.5 (python2.7) on files with

#!python

import xml.sax.handler
print xml.sax.handler
print xml.sax.saxutils

and

#!python

import os.path
print os.name

no AttributeError s.

Maybe we can close the issue?

[PCManticore]

@gyermolenko You need to run python over those files and you'll see a AttributeError: module 'xml.sax' has no attribute 'saxutils' error. I think this still needs to be fixed.

[Pierre-Sassoulas]

This still exists in 2.9.0:

five.py

import xml.sax.handler

print(xml.sax.handler)
print(xml.sax.saxutils)

pylint five.py:

------------------------------------
Your code has been rated at 10.00/10

python3 five.py:

<module 'xml.sax.handler' from '/usr/lib/python3.8/xml/sax/handler.py'>
Traceback (most recent call last):
  File "c.py", line 3, in <module>
    print(xml.sax.saxutils)
AttributeError: module 'xml.sax' has no attribute 'saxutils'

[kasium]

I also found this recently. After some debugging I found the source: https://github.com/PyCQA/pylint/blob/35254c29eb3a0f1c7847cfcb3451501a4180373d/pylint/checkers/variables.py#L1430

In short, if an import is found, only the first part (so e.g. os) is used for inferred, so that for all other checkers it seems, that import os was used, instead of os.path. Not sure if this can be changed easily

[Pierre-Sassoulas]

This seems promising @kasium. Do you want to handle the oldest issue still opened ? 😄 I don't know the scope of this either. You can dig a little and just report your finding if this happens to be bigger than what you're prepared to do.

[kasium]

@Pierre-Sassoulas so my first investigation is not the root cause.

As far as I could track down the issue, if a submodule is loaded, the parent is loaded as well, so that a member check like os.path can succeed. However. since the whole os module is loaded, checks like os.name will succeed as well.

Instead of loading the whole os module if a child is requested, we maybe just want to return a wrapper, which only let's checks for os.path succeed but not os.name. Not sure, how complicated this will be

[Pierre-Sassoulas]

if a submodule is loaded,

Do you mean by astroid or pylint ? Could you point to the specific code doing the loading ?