Raise ``AttributeInferenceError`` when ``getattr()`` receives an empty name

If `Module.getattr` received an empty string (as a result of inference for example),
`astroid` would have returned the same Module again, which leads to false positives
in pylint, since the expected output was of a different type.

Rather than allowing empty names to pass through `getattr()`, we simply raise
an error earlier.

Close PyCQA/pylint#2991

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/unittest_inference.py b/tests/unittest_inference.py
index 49ff6cdc..7f86de4d 100644
--- a/tests/unittest_inference.py
+++ b/tests/unittest_inference.py
@@ -5729,5 +5729,19 @@ def test_inferring_properties_multiple_time_does_not_mutate_locals_multiple_time
     assert len(a_locals) == 2
 
 
+def test_getattr_fails_on_empty_values():
+    code = """
+    import collections
+    collections
+    """
+    node = extract_node(code)
+    inferred = next(node.infer())
+    with pytest.raises(exceptions.InferenceError):
+        next(inferred.igetattr(""))
+
+    with pytest.raises(exceptions.AttributeInferenceError):
+        inferred.getattr("")
+
+
 if __name__ == "__main__":
     unittest.main()