seq: give a proper diagnostic for an invalid --format=% option

* src/seq.c (long_double_format): Handle '%' at end of string.
* tests/misc/seq [fmt-eos1, fmt-eos2]: New tests for the bug.
* NEWS: Mention this.
Reported by Pádraig Brady.

1 files changed, 4 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 34fda4e0f..bc1b47db5 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,10 @@ GNU coreutils NEWS                                    -*- outline -*-
   "rmdir --ignore-fail-on-non-empty" detects and ignores the failure
   in more cases when a directory is empty.
 
+  "seq -f % 1" would issue the erroneous diagnostic "seq: memory exhausted"
+  rather than reporting the invalid string format.
+  [bug introduced in coreutils-6.0]
+
 ** Improvements
 
   ls --color no longer outputs unnecessary escape sequences