Merge pull request #1526 from robertwb/no-object-attrs

Limit Python conversion on attribute access.

CHANGES.rst

@@ -54,6 +54,9 @@ Other changes
 
 * The `unraisable_tracebacks` now defaults to `True`.
 
+* Coercion of C++ containers to Python is no longer automatic on attribute
+  access (Github issue #1521).
+
 
 0.25.2 (2016-12-08)
 ===================

Cython/Compiler/ExprNodes.py

@@ -6578,7 +6578,10 @@ class AttributeNode(ExprNode):
         self.type = py_object_type
         self.is_py_attr = 1
         if not obj_type.is_pyobject and not obj_type.is_error:
-            if obj_type.can_coerce_to_pyobject(env):
+            # Expose python methods for immutable objects.
+            if (obj_type.is_string or obj_type.is_cpp_string
+                or obj_type.is_buffer or obj_type.is_numeric
+                or (obj_type.is_struct and obj_type.can_coerce_to_pyobject(env))):
                 if not immutable_obj:
                     self.obj = self.obj.coerce_to_pyobject(env)
             elif (obj_type.is_cfunction and (self.obj.is_name or self.obj.is_attribute)