mv: gnu test backup-dir regression fix

src/uu/mv/src/mv.rs

@@ -516,6 +516,21 @@ fn rename(
 ) -> io::Result<()> {
     let mut backup_path = None;
 
+    // If `no-target-directory` is specified, we treat the destination as a file.
+    // In that case, if there is a trailing forward slash, we remove it.
+    let to = if path_ends_with_terminator(to) && opts.no_target_dir {
+        let _to = to.to_string_lossy();
+        if cfg!(windows) {
+            Path::new(_to.trim_end_matches('\\')).to_path_buf()
+        } else {
+            Path::new(_to.trim_end_matches('/')).to_path_buf()
+        }
+    } else {
+        to.to_path_buf()
+    };
+
+    let to = &to;
+
     if to.exists() {
         if opts.update == UpdateMode::ReplaceIfOlder && opts.overwrite == OverwriteMode::Interactive
         {

tests/by-util/test_mv.rs

@@ -1778,3 +1778,24 @@ mod inter_partition_copying {
             .stderr_contains("Permission denied");
     }
 }
+
+#[cfg(unix)]
+#[test]
+fn test_mv_backup_when_dest_has_trailing_slash() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.mkdir("D");
+    at.mkdir("E");
+    at.touch("D/d_file");
+    at.touch("E/e_file");
+    scene
+        .ucmd()
+        .arg("-T")
+        .arg("--backup=numbered")
+        .arg("D")
+        .arg("E/")
+        .succeeds();
+    assert!(at.dir_exists("E.~1~"), "Backup folder not created");
+    assert!(at.file_exists("E.~1~/e_file"), "Backup file not created");
+    assert!(at.file_exists("E/d_file"), "source file didn't move");
+}