--version should just print the command name, not the path (#8921)

* --version should just print the command name, not the path

This will fix the parsing for old autoconf
Closes: #8880

* Update tests/by-util/test_mkdir.rs

Co-authored-by: Daniel Hofstetter <[email protected]>

---------

Co-authored-by: Daniel Hofstetter <[email protected]>

Author: sylvestre

src/uucore/src/lib/lib.rs

@@ -328,7 +328,14 @@ static UTIL_NAME: LazyLock<String> = LazyLock::new(|| {
     let is_man = usize::from(ARGV[base_index].eq("manpage"));
     let argv_index = base_index + is_man;
 
-    ARGV[argv_index].to_string_lossy().into_owned()
+    // Strip directory path to show only utility name
+    // (e.g., "mkdir" instead of "./target/debug/mkdir")
+    // in version output, error messages, and other user-facing output
+    std::path::Path::new(&ARGV[argv_index])
+        .file_name()
+        .unwrap_or(&ARGV[argv_index])
+        .to_string_lossy()
+        .into_owned()
 });
 
 /// Derive the utility name.

tests/by-util/test_mkdir.rs

@@ -24,6 +24,42 @@ fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails_with_code(1);
 }
 
+#[test]
+fn test_version_no_path() {
+    use std::process::Command;
+    use uutests::get_tests_binary;
+
+    // This test verifies that when an individual utility binary is invoked with its full path,
+    // the version output shows just "mkdir", not the full path like "/path/to/mkdir".
+    //
+    // Note: The multicall binary (coreutils) doesn't have this issue because it reads
+    // the utility name from ARGV[1], not ARGV[0]. This bug only affects individual binaries.
+
+    let tests_binary = get_tests_binary!();
+    let mkdir_binary_path = std::path::Path::new(tests_binary)
+        .parent()
+        .unwrap()
+        .join("mkdir");
+
+    // If the individual mkdir binary exists, test it
+    let output = if mkdir_binary_path.exists() {
+        // Invoke the individual mkdir binary with its full path
+        Command::new(&mkdir_binary_path)
+            .arg("--version")
+            .output()
+            .expect("Failed to execute mkdir binary")
+    } else {
+        // If only multicall binary exists, test that (it should already pass)
+        Command::new(tests_binary)
+            .args(["mkdir", "--version"])
+            .output()
+            .expect("Failed to execute mkdir via multicall binary")
+    };
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    assert!(stdout.starts_with("mkdir (uutils coreutils)"));
+}
+
 #[test]
 fn test_no_arg() {
     new_ucmd!()