[Python-checkins] cpython: Issue #24064: Property() docstrings are now writeable.

raymond.hettinger python-checkins at python.org
Wed May 13 10:10:22 CEST 2015


https://hg.python.org/cpython/rev/1e8a768fa0a5
changeset:   96010:1e8a768fa0a5
user:        Raymond Hettinger <python at rcn.com>
date:        Wed May 13 01:09:59 2015 -0700
summary:
  Issue #24064: Property() docstrings are now writeable.
(Patch by Berker Peksag.)

files:
  Doc/library/collections.rst  |   9 +++++++++
  Doc/whatsnew/3.5.rst         |  16 ++++++++++++++++
  Lib/test/test_collections.py |   8 ++++++++
  Lib/test/test_descr.py       |   5 ++++-
  Lib/test/test_property.py    |  22 ++++++++++++++++++++++
  Misc/NEWS                    |   3 +++
  Objects/descrobject.c        |   2 +-
  7 files changed, 63 insertions(+), 2 deletions(-)


diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -924,6 +924,15 @@
 
     >>> Point3D = namedtuple('Point3D', Point._fields + ('z',))
 
+Docstrings can be customized by making direct assignments to the ``__doc__``
+fields:
+
+   >>> Book = namedtuple('Book', ['id', 'title', 'authors'])
+   >>> Book.__doc__ = 'Hardcover book in active collection'
+   >>> Book.id = '13-digit ISBN'
+   >>> Book.title = 'Title of first printing'
+   >>> Book.author = 'List of authors sorted by last name'
+
 Default values can be implemented by using :meth:`_replace` to
 customize a prototype instance:
 
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -234,6 +234,10 @@
 * New Kazakh :ref:`codec <standard-encodings>` ``kz1048``.  (Contributed by
   Serhiy Storchaka in :issue:`22682`.)
 
+* Property docstrings are now writable. This is especially useful for
+  :func:`collections.namedtuple` docstrings.
+  (Contributed by Berker Peksag in :issue:`24064`.)
+
 * New Tajik :ref:`codec <standard-encodings>` ``koi8_t``.  (Contributed by
   Serhiy Storchaka in :issue:`22681`.)
 
@@ -283,6 +287,18 @@
   the full chained traceback, just like the interactive interpreter.
   (Contributed by Claudiu Popa in :issue:`17442`.)
 
+collections
+-----------
+
+* You can now update docstrings produced by :func:`collections.namedtuple`::
+
+    Point = namedtuple('Point', ['x', 'y'])
+    Point.__doc__ = 'ordered pair'
+    Point.x.__doc__ = 'abscissa'
+    Point.y.__doc__ = 'ordinate'
+
+  (Contributed by Berker Peksag in :issue:`24064`.)
+
 compileall
 ----------
 
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -199,6 +199,14 @@
         Point = namedtuple('Point', 'x y')
         self.assertEqual(Point.__doc__, 'Point(x, y)')
 
+    @unittest.skipIf(sys.flags.optimize >= 2,
+                     "Docstrings are omitted with -O2 and above")
+    def test_doc_writable(self):
+        Point = namedtuple('Point', 'x y')
+        self.assertEqual(Point.x.__doc__, 'Alias for field number 0')
+        Point.x.__doc__ = 'docstring for Point.x'
+        self.assertEqual(Point.x.__doc__, 'docstring for Point.x')
+
     def test_name_fixer(self):
         for spec, renamed in [
             [('efg', 'g%hi'),  ('efg', '_1')],                              # field with non-alpha char
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -2022,7 +2022,7 @@
         self.assertIs(raw.fset, C.__dict__['setx'])
         self.assertIs(raw.fdel, C.__dict__['delx'])
 
-        for attr in "__doc__", "fget", "fset", "fdel":
+        for attr in "fget", "fset", "fdel":
             try:
                 setattr(raw, attr, 42)
             except AttributeError as msg:
@@ -2033,6 +2033,9 @@
                 self.fail("expected AttributeError from trying to set readonly %r "
                           "attr on a property" % attr)
 
+        raw.__doc__ = 42
+        self.assertEqual(raw.__doc__, 42)
+
         class D(object):
             __getitem__ = property(lambda s: 1/0)
 
diff --git a/Lib/test/test_property.py b/Lib/test/test_property.py
--- a/Lib/test/test_property.py
+++ b/Lib/test/test_property.py
@@ -76,6 +76,13 @@
         """new docstring"""
         return 8
 
+class PropertyWritableDoc(object):
+
+    @property
+    def spam(self):
+        """Eggs"""
+        return "eggs"
+
 class PropertyTests(unittest.TestCase):
     def test_property_decorator_baseclass(self):
         # see #1620
@@ -150,6 +157,21 @@
                 foo = property(foo)
             C.foo.__isabstractmethod__
 
+    @unittest.skipIf(sys.flags.optimize >= 2,
+                     "Docstrings are omitted with -O2 and above")
+    def test_property_builtin_doc_writable(self):
+        p = property(doc='basic')
+        self.assertEqual(p.__doc__, 'basic')
+        p.__doc__ = 'extended'
+        self.assertEqual(p.__doc__, 'extended')
+
+    @unittest.skipIf(sys.flags.optimize >= 2,
+                     "Docstrings are omitted with -O2 and above")
+    def test_property_decorator_doc_writable(self):
+        sub = PropertyWritableDoc()
+        self.assertEqual(sub.__class__.spam.__doc__, 'Eggs')
+        sub.__class__.spam.__doc__ = 'Spam'
+        self.assertEqual(sub.__class__.spam.__doc__, 'Spam')
 
 # Issue 5890: subclasses of property do not preserve method __doc__ strings
 class PropertySub(property):
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -45,6 +45,9 @@
 - Issue #22486: Added the math.gcd() function.  The fractions.gcd() function now is
   deprecated.  Based on patch by Mark Dickinson.
 
+- Issue #24064: Property() docstrings are now writeable.
+  (Patch by Berker Peksag.)
+
 - Issue #22681: Added support for the koi8_t encoding.
 
 - Issue #22682: Added support for the kz1048 encoding.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1313,7 +1313,7 @@
     {"fget", T_OBJECT, offsetof(propertyobject, prop_get), READONLY},
     {"fset", T_OBJECT, offsetof(propertyobject, prop_set), READONLY},
     {"fdel", T_OBJECT, offsetof(propertyobject, prop_del), READONLY},
-    {"__doc__",  T_OBJECT, offsetof(propertyobject, prop_doc), READONLY},
+    {"__doc__",  T_OBJECT, offsetof(propertyobject, prop_doc), 0},
     {0}
 };
 

-- 
Repository URL: https://hg.python.org/cpython


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