New submission from Christian Heimes:
As reported by Duncan Booth at
http://permalink.gmane.org/gmane.comp.python.general/551183 the new
@spam.getter syntax modifies the property in place but it should create
a new one.
The patch is the first draft of a fix. I've to write unit tests to
verify the patch. It copies the property and as a bonus grabs the
__doc__ string from the getter if the doc string initially came from the
getter as well.
----------
assignee: tiran
components: Interpreter Core
files: py3k_copy_property.patch
keywords: patch, py3k
messages: 58598
nosy: gvanrossum, tiran
priority: high
severity: normal
status: open
title: New @spam.getter property syntax modifies the property in place
versions: Python 2.6, Python 3.0
Added file: http://bugs.python.org/file8947/py3k_copy_property.patch
__________________________________
Tracker <[EMAIL PROTECTED]>
<http://bugs.python.org/issue1620>
__________________________________
Index: Objects/descrobject.c
===================================================================
--- Objects/descrobject.c (revision 59478)
+++ Objects/descrobject.c (working copy)
@@ -1065,8 +1065,12 @@
PyObject *prop_set;
PyObject *prop_del;
PyObject *prop_doc;
+ int getter_doc;
} propertyobject;
+static PyObject * PyProperty_Copy(PyObject *, PyObject *, PyObject *,
+ PyObject *, PyObject *);
+
static PyMemberDef property_members[] = {
{"fget", T_OBJECT, offsetof(propertyobject, prop_get), READONLY},
{"fset", T_OBJECT, offsetof(propertyobject, prop_set), READONLY},
@@ -1075,53 +1079,37 @@
{0}
};
+
PyDoc_STRVAR(getter_doc,
"Descriptor to change the getter on a property.");
PyObject *
property_getter(PyObject *self, PyObject *getter)
{
- Py_XDECREF(((propertyobject *)self)->prop_get);
- if (getter == Py_None)
- getter = NULL;
- Py_XINCREF(getter);
- ((propertyobject *)self)->prop_get = getter;
- Py_INCREF(self);
- return self;
+ return PyProperty_Copy(self, getter, NULL, NULL, NULL);
}
+
PyDoc_STRVAR(setter_doc,
- "Descriptor to change the setter on a property.\n");
+ "Descriptor to change the setter on a property.");
PyObject *
property_setter(PyObject *self, PyObject *setter)
{
- Py_XDECREF(((propertyobject *)self)->prop_set);
- if (setter == Py_None)
- setter = NULL;
- Py_XINCREF(setter);
- ((propertyobject *)self)->prop_set = setter;
- Py_INCREF(self);
- return self;
+ return PyProperty_Copy(self, NULL, setter, NULL, NULL);
}
+
PyDoc_STRVAR(deleter_doc,
"Descriptor to change the deleter on a property.");
PyObject *
property_deleter(PyObject *self, PyObject *deleter)
{
- Py_XDECREF(((propertyobject *)self)->prop_del);
- if (deleter == Py_None)
- deleter = NULL;
- Py_XINCREF(deleter);
- ((propertyobject *)self)->prop_del = deleter;
- Py_INCREF(self);
- return self;
+ return PyProperty_Copy(self, NULL, NULL, deleter, NULL);
}
-
static PyMethodDef property_methods[] = {
{"getter", property_getter, METH_O, getter_doc},
{"setter", property_setter, METH_O, setter_doc},
@@ -1186,15 +1174,62 @@
return 0;
}
+static PyObject *
+PyProperty_Copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del,
+ PyObject *doc)
+{
+ propertyobject *pold = (propertyobject *)old;
+ propertyobject *pnew = NULL;
+ PyObject *new, *type;
+
+ type = PyObject_Type(old);
+ if (type == NULL)
+ return NULL;
+
+ if (get == NULL || get == Py_None) {
+ Py_XDECREF(get);
+ get = pold->prop_get ? pold->prop_get : Py_None;
+ }
+ if (set == NULL || set == Py_None) {
+ Py_XDECREF(set);
+ set = pold->prop_set ? pold->prop_set : Py_None;
+ }
+ if (del == NULL || del == Py_None) {
+ Py_XDECREF(del);
+ del = pold->prop_del ? pold->prop_del : Py_None;
+ }
+ if (doc == NULL || doc == Py_None) {
+ Py_XDECREF(doc);
+ doc = pold->prop_doc ? pold->prop_doc : Py_None;
+ }
+
+ new = PyObject_CallFunction(type, "OOOO", get, set, del, doc);
+ if (new == NULL)
+ return NULL;
+ pnew = (propertyobject *)new;
+
+ if (pold->getter_doc && get != Py_None) {
+ PyObject *get_doc = PyObject_GetAttrString(get, "__doc__");
+ if (get_doc != NULL) {
+ Py_XDECREF(pnew->prop_doc);
+ pnew->prop_doc = get_doc; /* get_doc already INCREF'd by GetAttr */
+ pnew->getter_doc = 1;
+ } else {
+ PyErr_Clear();
+ }
+ }
+ return new;
+}
+
static int
property_init(PyObject *self, PyObject *args, PyObject *kwds)
{
PyObject *get = NULL, *set = NULL, *del = NULL, *doc = NULL;
static char *kwlist[] = {"fget", "fset", "fdel", "doc", 0};
- propertyobject *gs = (propertyobject *)self;
-
+ propertyobject *prop = (propertyobject *)self;
+
if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOOO:property",
- kwlist, &get, &set, &del, &doc))
+ kwlist, &get, &set, &del, &doc))
return -1;
if (get == Py_None)
@@ -1209,22 +1244,24 @@
Py_XINCREF(del);
Py_XINCREF(doc);
+ prop->prop_get = get;
+ prop->prop_set = set;
+ prop->prop_del = del;
+ prop->prop_doc = doc;
+ prop->getter_doc = 0;
+
/* if no docstring given and the getter has one, use that one */
if ((doc == NULL || doc == Py_None) && get != NULL) {
PyObject *get_doc = PyObject_GetAttrString(get, "__doc__");
if (get_doc != NULL) {
- Py_XDECREF(doc);
- doc = get_doc; /* get_doc already INCREF'd by GetAttr */
+ Py_XDECREF(prop->prop_doc);
+ prop->prop_doc = get_doc; /* get_doc already INCREF'd by GetAttr */
+ prop->getter_doc = 1;
} else {
PyErr_Clear();
}
}
- gs->prop_get = get;
- gs->prop_set = set;
- gs->prop_del = del;
- gs->prop_doc = doc;
-
return 0;
}
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