bpo-41621: Document defaultdict's default_factory parameter (GH-21945)

sweeneyde · web-flow · commit d1ae57027fc3 · 2021-06-22T10:19:24.000-04:00
It defaults to None and is positional only.
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
@@ -707,9 +707,9 @@ stack manipulations such as ``dup``, ``drop``, ``swap``, ``over``, ``pick``,
 :class:`defaultdict` objects
 ----------------------------
 
-.. class:: defaultdict([default_factory[, ...]])
+.. class:: defaultdict(default_factory=None, /, [...])
 
-    Returns a new dictionary-like object.  :class:`defaultdict` is a subclass of the
+    Return a new dictionary-like object.  :class:`defaultdict` is a subclass of the
     built-in :class:`dict` class.  It overrides one method and adds one writable
     instance variable.  The remaining functionality is the same as for the
     :class:`dict` class and is not documented here.
diff --git a/Misc/NEWS.d/next/Documentation/2020-08-24-13-35-04.bpo-41621.nqaw9G.rst b/Misc/NEWS.d/next/Documentation/2020-08-24-13-35-04.bpo-41621.nqaw9G.rst
@@ -0,0 +1 @@
+Document that :class:`collections.defaultdict` parameter ``default_factory`` defaults to None and is positional-only.
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
@@ -2241,7 +2241,7 @@ defdict_init(PyObject *self, PyObject *args, PyObject *kwds)
 }
 
 PyDoc_STRVAR(defdict_doc,
-"defaultdict(default_factory[, ...]) --> dict with default factory\n\
+"defaultdict(default_factory=None, /, [...]) --> dict with default factory\n\
 \n\
 The default factory is called without arguments to produce\n\
 a new value when a key is not present, in __getitem__ only.\n\

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Document that :class:`collections.defaultdict` parameter ``default_factory`` defaults to None and is positional-only.
Original file line number	Diff line number	Diff line change
`@@ -2241,7 +2241,7 @@ defdict_init(PyObject self, PyObject args, PyObject *kwds)`
`2241`	`2241`	`}`
`2242`	`2242`
`2243`	`2243`	`PyDoc_STRVAR(defdict_doc,`
`2244`		`-"defaultdict(default_factory[, ...]) --> dict with default factory\n\`
	`2244`	`+"defaultdict(default_factory=None, /, [...]) --> dict with default factory\n\`
`2245`	`2245`	`\n\`
`2246`	`2246`	`The default factory is called without arguments to produce\n\`
`2247`	`2247`	`a new value when a key is not present, in __getitem__ only.\n\`