Refs #25629 -- Added `arity` class attribute to `Func` expressions

2 files changed, 13 insertions, 0 deletions

diff --git a/docs/ref/models/expressions.txt b/docs/ref/models/expressions.txt
index 87c3108509..98ba323171 100644
--- a/docs/ref/models/expressions.txt
+++ b/docs/ref/models/expressions.txt
@@ -252,6 +252,15 @@ The ``Func`` API is as follows:
         A class attribute that denotes the character used to join the list of
         ``expressions`` together. Defaults to ``', '``.
 
+    .. attribute:: arity
+
+        .. versionadded:: 1.10
+
+        A class attribute that denotes the number of arguments the function
+        accepts. If this attribute is set and the function is called with a
+        different number of expressions, ``TypeError`` will be raised. Defaults
+        to ``None``.
+
 The ``*expressions`` argument is a list of positional expressions that the
 function will be applied to. The expressions will be converted to strings,
 joined together with ``arg_joiner``, and then interpolated into the ``template``
diff --git a/docs/releases/1.10.txt b/docs/releases/1.10.txt
index 8846dce242..20afbd93b8 100644
--- a/docs/releases/1.10.txt
+++ b/docs/releases/1.10.txt
@@ -175,6 +175,10 @@ Models
   accessible as a descriptor on the proxied model class and may be referenced in
   queryset filtering.
 
+* The :attr:`~django.db.models.Func.arity` class attribute is added to
+  :class:`~django.db.models.Func`. This attribute can be used to set the number
+  of arguments the function accepts.
+
 Requests and Responses
 ^^^^^^^^^^^^^^^^^^^^^^