chroot: report ENAMETOOLONG instead of "no such directory" for long NEWROOT

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

@@ -20,6 +20,7 @@ chroot-error-no-group-specified = no group specified for unknown uid: { $uid }
 chroot-error-no-such-user = invalid user
 chroot-error-no-such-group = invalid group
 chroot-error-no-such-directory = cannot change root directory to { $dir }: no such directory
+chroot-error-cannot-stat = cannot change root directory to { $dir }: { $err }
 chroot-error-set-gid-failed = cannot set gid to { $gid }: { $err }
 chroot-error-set-groups-failed = cannot set groups: { $err }
 chroot-error-set-user-failed = cannot set user to { $user }: { $err }

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

@@ -20,6 +20,7 @@ chroot-error-no-group-specified = aucun groupe spécifié pour l'uid inconnu : {
 chroot-error-no-such-user = utilisateur invalide
 chroot-error-no-such-group = groupe invalide
 chroot-error-no-such-directory = impossible de changer le répertoire racine vers { $dir } : aucun répertoire de ce type
+chroot-error-cannot-stat = impossible de changer le répertoire racine vers { $dir } : { $err }
 chroot-error-set-gid-failed = impossible de définir le gid à { $gid } : { $err }
 chroot-error-set-groups-failed = impossible de définir les groupes : { $err }
 chroot-error-set-user-failed = impossible de définir l'utilisateur à { $user } : { $err }

src/uu/chroot/src/chroot.rs

@@ -194,6 +194,14 @@
         options.chroot_target = resolved;
     }
 
+    // Probe the path with `metadata` so the *original* I/O error reaches the
+    // user. `Path::is_dir()` swallows that error and reports `false` for any
+    // failure — including `ENAMETOOLONG` (a 256-char path on Linux), which GNU
+    // surfaces as "File name too long". Without this, a too-long NEWROOT
+    // would be misreported as "no such directory".
+    if let Err(e) = std::fs::metadata(&options.newroot) {
+        return Err(ChrootError::CannotStat(options.newroot, e).into());
+    }
     if !options.newroot.is_dir() {
         return Err(ChrootError::NoSuchDirectory(options.newroot).into());
     }

src/uu/chroot/src/error.rs

@@ -56,6 +56,10 @@
     #[error("{}", translate!("chroot-error-no-such-directory", "dir" => _0.quote()))]
     NoSuchDirectory(PathBuf),
 
+    /// The given path could not be stat'd (e.g. ENAMETOOLONG, EACCES).
+    #[error("{}", translate!("chroot-error-cannot-stat", "dir" => _0.quote(), "err" => _1))]
+    CannotStat(PathBuf, #[source] Error),
+
     /// The call to `setgid()` failed.
     #[error("{}", translate!("chroot-error-set-gid-failed", "gid" => _0, "err" => _1))]
     SetGidFailed(String, #[source] Error),

tests/by-util/test_chroot.rs

@@ -56,6 +56,22 @@
         .stderr_is("chroot: cannot change root directory to 'a': no such directory\n");
 }
 
+#[test]
+#[cfg(not(target_os = "android"))]
+fn test_filename_too_long() {
+    // Regression for #13156: a NEWROOT longer than NAME_MAX (255 bytes on
+    // Linux) used to be misreported as "no such directory" because
+    // `Path::is_dir()` swallows ENAMETOOLONG. GNU surfaces the real error.
+    let long_name = "A".repeat(256);
+    let expected = format!(
+        "chroot: cannot change root directory to '{long_name}': File name too long (os error 63)\n"
+    );
+    new_ucmd!()
+        .arg(&long_name)
+        .fails_with_code(125)
+        .stderr_is(expected);
+}
+
 #[test]
 fn test_multiple_group_args() {
     let ts = TestScenario::new(util_name!());