Fixed bug #1620: New @spam.getter property syntax modifies the property in place.

I added also the feature that a @prop.getter decorator does not overwrite the doc string of the property if it was given as an argument to property().

Lib/test/test_property.py

@@ -0,0 +1,98 @@
+# Test case for property
+# more tests are in test_descr
+
+import unittest
+from test.test_support import run_unittest
+
+class PropertyBase(Exception):
+    pass
+
+class PropertyGet(PropertyBase):
+    pass
+
+class PropertySet(PropertyBase):
+    pass
+
+class PropertyDel(PropertyBase):
+    pass
+
+class BaseClass(object):
+    def __init__(self):
+        self._spam = 5
+
+    @property
+    def spam(self):
+        """BaseClass.getter"""
+        return self._spam
+
+    @spam.setter
+    def spam(self, value):
+        self._spam = value
+
+    @spam.deleter
+    def spam(self):
+        del self._spam
+
+class SubClass(BaseClass):
+
+    @BaseClass.spam.getter
+    def spam(self):
+        """SubClass.getter"""
+        raise PropertyGet(self._spam)
+
+    @spam.setter
+    def spam(self, value):
+        raise PropertySet(self._spam)
+
+    @spam.deleter
+    def spam(self):
+        raise PropertyDel(self._spam)
+
+class PropertyDocBase(object):
+    _spam = 1
+    def _get_spam(self):
+        return self._spam
+    spam = property(_get_spam, doc="spam spam spam")
+
+class PropertyDocSub(PropertyDocBase):
+    @PropertyDocBase.spam.getter
+    def spam(self):
+        """The decorator does not use this doc string"""
+        return self._spam
+
+class PropertyTests(unittest.TestCase):
+    def test_property_decorator_baseclass(self):
+        # see #1620
+        base = BaseClass()
+        self.assertEqual(base.spam, 5)
+        self.assertEqual(base._spam, 5)
+        base.spam = 10
+        self.assertEqual(base.spam, 10)
+        self.assertEqual(base._spam, 10)
+        delattr(base, "spam")
+        self.assert_(not hasattr(base, "spam"))
+        self.assert_(not hasattr(base, "_spam"))
+        base.spam = 20
+        self.assertEqual(base.spam, 20)
+        self.assertEqual(base._spam, 20)
+        self.assertEqual(base.__class__.spam.__doc__, "BaseClass.getter")
+
+    def test_property_decorator_subclass(self):
+        # see #1620
+        sub = SubClass()
+        self.assertRaises(PropertyGet, getattr, sub, "spam")
+        self.assertRaises(PropertySet, setattr, sub, "spam", None)
+        self.assertRaises(PropertyDel, delattr, sub, "spam")
+        self.assertEqual(sub.__class__.spam.__doc__, "SubClass.getter")
+
+    def test_property_decorator_doc(self):
+        base = PropertyDocBase()
+        sub = PropertyDocSub()
+        self.assertEqual(base.__class__.spam.__doc__, "spam spam spam")
+        self.assertEqual(sub.__class__.spam.__doc__, "spam spam spam")
+
+def test_main():
+    run_unittest(PropertyTests)
+
+if __name__ == '__main__':
+    test_main()