Don't emit 'protected-access' if the attribute is accessed using a property defined at the class level.

3 files changed, 22 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 7b70fa7..f7c3b90 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -63,6 +63,9 @@ ChangeLog for Pylint
     * Look in the metaclass, if defined, for members not found in the current
       class. Closes issue #306.
 
+    * Don't emit 'protected-access' if the attribute is accessed using
+      a property defined at the class level.
+
 2014-07-26  --  1.3.0
 
     * Allow hanging continued indentation for implicitly concatenated
diff --git a/checkers/classes.py b/checkers/classes.py
index 90b2fbe..ebca3f2 100644
--- a/checkers/classes.py
+++ b/checkers/classes.py
@@ -27,7 +27,7 @@ from pylint.interfaces import IAstroidChecker
 from pylint.checkers import BaseChecker
 from pylint.checkers.utils import (
     PYMETHODS, overrides_a_method, check_messages, is_attr_private,
-    is_attr_protected, node_frame_class, safe_infer)
+    is_attr_protected, node_frame_class, safe_infer, is_builtin_object)
 
 if sys.version_info >= (3, 0):
     NEXT_METHOD = '__next__'
@@ -581,6 +581,23 @@ a metaclass class method.'}
             # We are in a class, one remaining valid cases, Klass._attr inside
             # Klass
             if not (callee == klass.name or callee in klass.basenames):
+                # Detect property assignments in the body of the class.
+                # This is acceptable:
+                #
+                # class A:
+                #     b = property(lambda: self._b)
+
+                stmt = node.parent.statement()
+                try:
+                    if (isinstance(stmt, astroid.Assign) and
+                            (stmt in klass.body or klass.parent_of(stmt)) and
+                            isinstance(stmt.value, astroid.CallFunc) and
+                            isinstance(stmt.value.func, astroid.Name) and
+                            stmt.value.func.name == 'property' and
+                            is_builtin_object(next(stmt.value.func.infer(), None))):
+                        return
+                except astroid.InferenceError:
+                    pass
                 self.add_message('protected-access', node=node, args=attrname)
 
     def visit_name(self, node):
diff --git a/test/input/func_noerror_classes_protected_member_access.py b/test/input/func_noerror_classes_protected_member_access.py
index bef1bff..eeff97d 100644
--- a/test/input/func_noerror_classes_protected_member_access.py
+++ b/test/input/func_noerror_classes_protected_member_access.py
@@ -22,3 +22,4 @@ class A3123(object):
 
     smeth = staticmethod(smeth)
 
+    prop = property(lambda self: self._protected)