uu: updated error message for mv on overwriting non-empty directory inside destination directory

src/uu/mv/locales/en-US.ftl

@@ -31,6 +31,7 @@ mv-error-extra-operand = mv: extra operand {$operand}
 mv-error-backup-might-destroy-source = backing up {$target} might destroy source;  {$source} not moved
 mv-error-will-not-overwrite-just-created = will not overwrite just-created '{$target}' with '{$source}'
 mv-error-not-replacing = not replacing {$target}
+mv-error-cannot-overwrite = cannot overwrite {$target}
 mv-error-cannot-move = cannot move {$source} to {$target}
 mv-error-directory-not-empty = Directory not empty
 mv-error-dangling-symlink = can't determine symlink type, since it is dangling

src/uu/mv/locales/fr-FR.ftl

@@ -31,6 +31,7 @@ mv-error-extra-operand = mv : opérande supplémentaire {$operand}
 mv-error-backup-might-destroy-source = sauvegarder {$target} pourrait détruire la source ; {$source} non déplacé
 mv-error-will-not-overwrite-just-created = ne va pas écraser le fichier qui vient d'être créé '{$target}' avec '{$source}'
 mv-error-not-replacing = ne remplace pas {$target}
+mv-error-cannot-overwrite = impossible d'écraser ${target}
 mv-error-cannot-move = impossible de déplacer {$source} vers {$target}
 mv-error-directory-not-empty = Répertoire non vide
 mv-error-dangling-symlink = impossible de déterminer le type de lien symbolique, car il est suspendu

src/uu/mv/src/mv.rs

@@ -675,9 +675,9 @@ fn move_files_into_dir(files: &[PathBuf], target_dir: &Path, options: &Options)
         ) {
             Err(e) if e.to_string().is_empty() => set_exit_code(1),
             Err(e) => {
-                let e = e.map_err_context(|| {
-                    translate!("mv-error-cannot-move", "source" => sourcepath.quote(), "target" => targetpath.quote())
-                });
+                let e = e.map_err_context(
+                    || translate!("mv-error-cannot-overwrite", "target" => targetpath.quote()),
+                );
                 match display_manager {
                     Some(ref pb) => pb.suspend(|| show!(e)),
                     None => show!(e),

tests/by-util/test_mv.rs

@@ -1427,6 +1427,46 @@ fn test_mv_overwrite_nonempty_dir() {
     assert!(at.dir_exists(dir_b));
 }
 
+#[test]
+fn test_mv_overwrite_nonempty_dir_error() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    let dir_a = "test_mv_overwrite_nonempty_dir_error_a";
+    let dir_b = "test_mv_overwrite_nonempty_dir_error_b";
+    let shared_dir = "dir";
+    let dummy_dir_a = &format!("{dir_a}/{shared_dir}");
+
+    let dummy_dir_b = {
+        // for Windows OS which uses back slash for paths on
+        // err msg
+        #[cfg(not(unix))]
+        {
+            &format!("{dir_b}\\{shared_dir}")
+        }
+        // for Unix OS which uses forward slash for paths on
+        // err msg
+        #[cfg(unix)]
+        {
+            &format!("{dir_b}/{shared_dir}")
+        }
+    };
+    let dummy_file = &format!("{dir_b}/{shared_dir}/file");
+
+    at.mkdir(dir_a);
+    at.mkdir(dummy_dir_a);
+    at.mkdir(dir_b);
+    at.mkdir(dummy_dir_b);
+    at.touch(dummy_file);
+
+    // Not same error as GNU; the error message is a rust builtin as mentioned in
+    // https://github.com/uutils/coreutils/issues/5102
+    // Current: "mv: cannot overwrite: A non-empty directory: 'b' exists at destination"
+    // GNU:     "mv: cannot overwrite 'b': Directory not empty"
+
+    ucmd.arg(dummy_dir_a).arg(dir_b).fails().stderr_is(format!(
+        "mv: cannot overwrite '{dummy_dir_b}': Directory not empty\n"
+    ));
+}
+
 #[test]
 fn test_mv_backup_dir() {
     let (at, mut ucmd) = at_and_ucmd!();