1 files changed, 63 insertions, 0 deletions
diff --git a/tests/mv/symlink-onto-hardlink-to-self.sh b/tests/mv/symlink-onto-hardlink-to-self.sh
new file mode 100755
index 0000000..a230c87
--- /dev/null
+++ b/tests/mv/symlink-onto-hardlink-to-self.sh
@@ -0,0 +1,63 @@
+#!/bin/sh
+# Demonstrate that when moving a symlink onto a hardlink-to-that-symlink,
+# an error is presented.  Depending on your kernel (e.g., Linux, Solaris,
+# but not NetBSD), prior to coreutils-8.16, the mv would successfully perform
+# a no-op.  I.e., surprisingly, mv s1 s2 would succeed, yet fail to remove s1.
+
+# Copyright (C) 2012-2020 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ mv
+
+# Create a file f, and a symlink s1 to that file.
+touch f || framework_failure_
+ln -s f s2 || framework_failure_
+
+# Attempt to create a hard link to that symlink.
+# On some systems, it's not possible: they create a hard link to the referent.
+ln s2 s1 || framework_failure_
+
+# If s1 is not a symlink, skip this test.
+test -h s1 \
+  || skip_ your kernel or file system cannot create a hard link to a symlink
+
+for opt in '' --backup; do
+
+  if test "$opt" = --backup; then
+    mv $opt s1 s2 > out 2>&1 || fail=1
+    compare /dev/null out || fail=1
+
+    # Ensure that s1 is gone.
+    test -e s1 && fail=1
+
+    # With --backup, ensure that the backup file was created.
+    ref=$(readlink s2~) || fail=1
+    test "$ref" = f || fail=1
+  else
+    echo "mv: 's1' and 's2' are the same file" > exp
+    mv $opt s1 s2 2>err && fail=1
+    compare exp err || fail=1
+
+    # Ensure that s1 is still present.
+    test -e s1 || fail=1
+
+    # Without --backup, ensure there is no backup file.
+    test -e s2~ && fail=1
+  fi
+
+done
+
+Exit $fail