False Positive no-member (E1101)

[ameily]

I'm seeing a false positive for no-member when there are two exception blocks that reuse the exception name. Here is the code block that is triggering the false positive:

def test_pylint():
    try:
        fp = open('some-file', 'r')
    except ValueError as e:
        print('error:', str(e))
        return

    try:
        fp.write(b'something')
    except OSError as e:
        print('error:', e.strerror)
    finally:
        fp.close()

The error pylint is reporting:

************* Module test_pylint
Core\test_pylint.py:13:24: E1101: Instance of 'ValueError' has no 'strerror' member (no-member)

I understand that open() may never raise a ValueError, I just used it to demonstrate the issue.

Steps to reproduce

1. Create two separate and sequential try...except blocks that catch different exceptions. The secondtry...except must reference a member in the exception that is not available in the first exception (see above example code)
2. Run pylint
3. See there is a false positive for no-member on the second exception block.

Current behavior

There is a no-member error on the second exception block.

Expected behavior

pylint properly detects that the second exception block catches a different exception type and there is no no-member false positives.

pylint --version output

pylint 2.3.1
astroid 2.2.2
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit (AMD64)]

[ameily]

I have confirmed that this was not an issue in pylint 2.2.2, astroid 2.0.0

[PCManticore]

Thanks for reporting an issue. This is similar to #2777 so I'm going to close this one. What's happening is described in my comment here, basically we infer e as both OSerror and ValueError, even though e is bound in that except handler as OSError.