rm: disallow --n alias for --no-preserve-root

* src/rm.c (main): Ensure the full --no-preserve-root
option is specified, rather than allowing --n etc.
* tests/rm/r-root.sh: Add a test case.
* NEWS: Mention the change in behavior.

Improved by Jim Meyering.
Fixes http://bugs.gnu.org/24604

1 files changed, 3 insertions, 0 deletions

diff --git a/src/rm.c b/src/rm.c
index 13a5714c3..2c54405f7 100644
--- a/src/rm.c
+++ b/src/rm.c
@@ -287,6 +287,9 @@ main (int argc, char **argv)
           break;
 
         case NO_PRESERVE_ROOT:
+          if (! STREQ (argv[optind - 1], "--no-preserve-root"))
+            error (EXIT_FAILURE, 0,
+                   _("you may not abbreviate the --no-preserve-root option"));
           preserve_root = false;
           break;