[PATCH 4/4] strftime: fix stale errno upon field width overflow

[Pádraig Brady]

The random error can be triggered with:
  $ LC_ALL=C TZ=UTC0 date -d @0 '+%9223372036854775808Y'
  date: fprintftime error: No such file or directory

With the fix it gives:
  date: fprintftime error: Numerical result out of range

This issue was introduced in commit 42ea6679 (Nov 2025).

* lib/strftime.c (__strftime_internal): Set errno=ERANGE
upon width overflow.
---
 lib/strftime.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/strftime.c b/lib/strftime.c
index 76c7e57b70..94a771155f 100644
--- a/lib/strftime.c
+++ b/lib/strftime.c
@@ -1441,7 +1441,10 @@ __strftime_internal (STREAM_OR_CHAR_T *s, STRFTIME_ARG 
(size_t maxsize)
             {
               if (ckd_mul (&width, width, 10)
                   || ckd_add (&width, width, *f - L_('0')))
-                return FAILURE;
+                {
+                  errno = ERANGE;
+                  return FAILURE;
+                }
               ++f;
             }
           while (ISDIGIT (*f));
-- 
2.56.0