[3.13] gh-140196: Add constructor behavior changes in ast.rst for python 3.13 (GH...

(cherry picked from commit fae5761a762a587b48430cbcd6e1886034ae8130)

Co-authored-by: Parman Mohammadalizadeh <prmma23@gmail.com>

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index ec6a4a82d6fd7f313c5bbf624a755f86ba083f05..42728b1394a372828d71949bf2cdda1a797e23a8 100644 (file)
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -134,6 +134,14 @@ Node classes
    Simple indices are represented by their value, extended slices are
    represented as tuples.
 
+.. versionchanged:: 3.13
+
+    AST node constructors were changed to provide sensible defaults for omitted
+    fields: optional fields now default to ``None``, list fields default to an
+    empty list, and fields of type :class:`!ast.expr_context` default to
+    :class:`Load() <ast.Load>`. Previously, omitted attributes would not exist on constructed
+    nodes (accessing them raised :exc:`AttributeError`).
+
 .. deprecated:: 3.8
 
    Old classes :class:`!ast.Num`, :class:`!ast.Str`, :class:`!ast.Bytes`,