Fix: copy property object if accessor functions are changed.

Author: fangerer

graalpython/com.oracle.graal.python.test/src/tests/test_property.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -72,6 +72,22 @@ def prop_x(self):
         del self._x
 
 
+class X(object):
+    @property
+    def prop_x(self):
+        return self._prop_x
+
+    @prop_x.setter
+    def prop_x(self, new_val):
+        self._prop_x = new_val
+        return new_val
+
+class Y(X):
+    @X.prop_x.setter
+    def prop_x(self, ax):
+        X.prop_x.fset(self, ax)
+
+
 def test_properties():
     c = C(10)
     assert c.prop_x == 10
@@ -96,3 +112,5 @@ def test_properties():
     except AttributeError:
         not_found = True
     assert not_found
+
+    assert X.prop_x is not Y.prop_x

graalpython/lib-graalpython/property.py

@@ -96,16 +96,13 @@ def __delete__(self, instance):
         return self.fdel(instance)
 
     def setter(self, func):
-        self.fset = func
-        return self
+        return self.__copy(fset=func)
 
     def deleter(self, func):
-        self.fdel = func
-        return self
+        return self.__copy(fdel=func)
 
     def getter(self, func):
-        self.fget = func
-        return self
+        return self.__copy(fget=func)
 
     def __repr__(self):
         return "'".join([
@@ -115,3 +112,9 @@ def __repr__(self):
             getattr(self._owner, "__name__", str(self._owner)),
             " objects>"
         ])
+
+    def __copy(self, fget=None, fset=None, fdel=None):
+        _fget = fget if fget is not None else self.fget
+        _fset = fset if fset is not None else self.fset
+        _fdel = fdel if fdel is not None else self.fdel
+        return type(self)(fget=_fget, fset=_fset, fdel=_fdel, doc=self.doc, name=self.name)

graalpython/lib-graalpython/python_cext.py

@@ -972,17 +972,18 @@ def AddMember(primary, tpDict, name, memberType, offset, canSet, doc):
     # the ReadMemberFunctions and WriteMemberFunctions don't have a wrapper to
     # convert arguments to Sulong, so we can avoid boxing the offsets into PInts
     pclass = to_java_type(primary)
-    member = property()
     getter = ReadMemberFunctions[memberType]
     def member_getter(self):
         return to_java(getter(to_sulong(self), TrufflePInt_AsPrimitive(offset, 1, 8)))
-    member.getter(member_getter)
+    member_fget = member_getter
+    member_fset = None
     if canSet:
         setter = WriteMemberFunctions[memberType]
         def member_setter(self, value):
             setter(to_sulong(self), TrufflePInt_AsPrimitive(offset, 1, 8), to_sulong(value))
-        member.setter(member_setter)
-    member.__doc__ = doc
+        member_fset = member_setter
+    # nb: do not use member.setter/getter because they create copies of the property
+    member = property(fget=member_fget, fset=member_fset, doc=doc)
     type_dict = to_java(tpDict)
     type_dict[name] = member