From 533ff6fc0622bfae5d13d3a3838fbec3d9d21092 Mon Sep 17 00:00:00 2001
From: Georg Brandl <georg@python.org>
Date: Wed, 8 Mar 2006 18:09:27 +0000
Subject: Patch #1434038: property() now uses the getter's docstring if there
is no "doc" argument given. This makes it possible to legitimately use
property() as a decorator to produce a read-only property.
---
Doc/lib/libfuncs.tex | 5 +++++
Lib/test/test_descr.py | 12 ++++++++++++
Misc/NEWS | 4 ++++
Objects/descrobject.c | 12 ++++++++++++
4 files changed, 33 insertions(+)
diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex
index 12dbc0c..9b6bfe9 100644
--- a/Doc/lib/libfuncs.tex
+++ b/Doc/lib/libfuncs.tex
@@ -771,7 +771,12 @@ class C(object):
x = property(getx, setx, delx, "I'm the 'x' property.")
\end{verbatim}
+ If given, \var{doc} will be the docstring of the property attribute.
+ Otherwise, the property will copy \var{fget}'s docstring (if it
+ exists).
+
\versionadded{2.2}
+ \versionchanged[Use \var{fget}'s docstring if no \var{doc} given]{2.5}
\end{funcdesc}
\begin{funcdesc}{range}{\optional{start,} stop\optional{, step}}
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 68a11fa..57a8f44 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -2008,6 +2008,18 @@ def properties():
else:
raise TestFailed, "expected ZeroDivisionError from bad property"
+ class E(object):
+ def getter(self):
+ "getter method"
+ return 0
+ def setter(self, value):
+ "setter method"
+ pass
+ prop = property(getter)
+ vereq(prop.__doc__, "getter method")
+ prop2 = property(fset=setter)
+ vereq(prop2.__doc__, None)
+
def supers():
if verbose: print "Testing super..."
diff --git a/Misc/NEWS b/Misc/NEWS
index 6657f3a..ed4e97b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@ What's New in Python 2.5 alpha 1?
Core and builtins
-----------------
+- Patch #1434038: property() now uses the getter's docstring if there is
+ no "doc" argument given. This makes it possible to legitimately use
+ property() as a decorator to produce a read-only property.
+
- PEP 357, patch 1436368: add an __index__ method to int/long and a matching
nb_index slot to the PyNumberMethods struct. The slot is consulted instead
of requiring an int or long in slicing and a few other contexts, enabling
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index b96ad6e..9494062 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1081,6 +1081,8 @@ PyWrapper_New(PyObject *d, PyObject *self)
class property(object):
def __init__(self, fget=None, fset=None, fdel=None, doc=None):
+ if doc is None and fget is not None and hasattr(fget, "__doc__"):
+ doc = fget.__doc__
self.__get = fget
self.__set = fset
self.__del = fdel
@@ -1182,6 +1184,7 @@ static int
property_init(PyObject *self, PyObject *args, PyObject *kwds)
{
PyObject *get = NULL, *set = NULL, *del = NULL, *doc = NULL;
+ PyObject *get_doc = NULL;
static char *kwlist[] = {"fget", "fset", "fdel", "doc", 0};
propertyobject *gs = (propertyobject *)self;
@@ -1196,6 +1199,15 @@ property_init(PyObject *self, PyObject *args, PyObject *kwds)
if (del == Py_None)
del = NULL;
+ /* if no docstring given and the getter has one, use that one */
+ if ((doc == NULL || doc == Py_None) && get != NULL &&
+ PyObject_HasAttrString(get, "__doc__")) {
+ if (!(get_doc = PyObject_GetAttrString(get, "__doc__")))
+ return -1;
+ Py_DECREF(get_doc); /* it is INCREF'd again below */
+ doc = get_doc;
+ }
+
Py_XINCREF(get);
Py_XINCREF(set);
Py_XINCREF(del);
--
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