Merge 3e7dc2d into 3dc5fc6

confidence.py

@@ -4,6 +4,7 @@
 from itertools import chain, product
 from os import environ, path
 import re
+import warnings
 
 import yaml
 
@@ -81,6 +82,12 @@ def _split_keys(mapping, separator='.'):
             # use rest as the new key of value, recursively split that and update value
             value = _split_keys({rest: value}, separator)
 
+        if key in _COLLIDING_KEYS:
+            # warn about configured keys colliding with Configuration members
+            warnings.warn('key {key} collides with member of Configuration type, use get() method to retrieve key '
+                          '{key}'.format(key=key),
+                          UserWarning)
+
         # merge the result so far with the (possibly updated / fixed / split) current key and value
         _merge(result, {key: value})
 
@@ -200,6 +207,9 @@ def __dir__(self):
         return sorted(set(chain(super().__dir__(), self.keys())))
 
 
+_COLLIDING_KEYS = frozenset(dir(Configuration()))
+
+
 class NotConfigured(Configuration):
     """
     Sentinel value to signal there is no value for a requested key.

tests/test_namespace.py

@@ -1,4 +1,5 @@
-from collections import Mapping
+from collections.abc import Mapping
+from unittest.mock import patch
 
 import pytest
 
@@ -46,6 +47,20 @@ def test_not_configured():
     assert str(subject.does_nope_exist) == repr(subject.does.nope.exist)
 
 
+def test_collisions():
+    with patch('confidence.warnings') as warnings:
+        subject = Configuration({'key': 'value', 'keys': [1, 2], '_separator': '_'})
+
+    for collision in ('keys', '_separator'):
+        warnings.warn.assert_any_call('key {key} collides with member of Configuration type, use get() method to '
+                                      'retrieve key {key}'.format(key=collision),
+                                      UserWarning)
+
+    assert subject.key == 'value'
+    assert callable(subject.keys)
+    assert subject._separator == '.'
+
+
 def test_dir():
     subject = Configuration({'key1': 'value', 'key2': 5, 'namespace.key3': False})