Merge branch 'feature/upstream' into develop

1 files changed, 16 insertions, 3 deletions

diff --git a/lib/printf-args.c b/lib/printf-args.c
index c2022503..b83ec1e8 100644
--- a/lib/printf-args.c
+++ b/lib/printf-args.c
@@ -1,5 +1,5 @@
 /* Decomposed printf argument list.
-   Copyright (C) 1999, 2002-2003, 2005-2007, 2009-2024 Free Software
+   Copyright (C) 1999, 2002-2003, 2005-2007, 2009-2025 Free Software
    Foundation, Inc.
 
    This file is free software: you can redistribute it and/or modify
@@ -32,6 +32,9 @@
 /* Get INT_WIDTH.  */
 #include <limits.h>
 
+/* Get abort().  */
+#include <stdlib.h>
+
 #ifdef STATIC
 STATIC
 #endif
@@ -296,9 +299,19 @@ PRINTF_FETCHARGS (va_list args, arguments *a)
           }
         break;
 #endif
-      default:
-        /* Unknown type.  */
+      case TYPE_NONE:
+        /* Argument i is not used by any directive, but some argument with
+           number > i is used by a format directive.  POSIX says that this
+           is invalid:
+             "When numbered argument specifications are used, specifying the
+              Nth argument requires that all the leading arguments, from the
+              first to the (N-1)th, are specified in the format string."
+           The reason is that we cannot know how many bytes to skip in the
+           va_arg sequence.  */
         return -1;
+      default:
+        /* Unknown type.  Should not happen.  */
+        abort ();
       }
   return 0;
 }