Add spaces around the ":=" operator in ast_unparse.c (GH-19568)

Author: hakancelikdev

Lib/test/test_future.py

@@ -296,8 +296,8 @@ def test_annotations(self):
         eq('f((x for x in a), 2)')
         eq('(((a)))', 'a')
         eq('(((a, b)))', '(a, b)')
-        eq("(x:=10)")
-        eq("f'{(x:=10):=10}'")
+        eq("(x := 10)")
+        eq("f'{(x := 10):=10}'")
         eq("1 + 2 + 3")
 
     def test_fstring_debug_annotations(self):

Python/ast_unparse.c

@@ -829,7 +829,7 @@ append_named_expr(_PyUnicodeWriter *writer, expr_ty e, int level)
 {
     APPEND_STR_IF(level > PR_TUPLE, "(");
     APPEND_EXPR(e->v.NamedExpr.target, PR_ATOM);
-    APPEND_STR(":=");
+    APPEND_STR(" := ");
     APPEND_EXPR(e->v.NamedExpr.value, PR_ATOM);
     APPEND_STR_IF(level > PR_TUPLE, ")");
     return 0;