fix(numfmt): Read lines only up to null byte (as GNU does)

src/uu/numfmt/src/numfmt.rs

@@ -72,11 +72,18 @@ fn write_line<W: std::io::Write>(
     input_line: &[u8],
     options: &NumfmtOptions,
 ) -> UResult<()> {
+    // Read lines only up to null byte (as GNU does)
+    let line = input_line
+        .iter()
+        .take_while(|&&b| b != b'\0')
+        .cloned()
+        .collect::<Vec<u8>>();
+
     let handled_line = if options.delimiter.is_some() {
-        write_formatted_with_delimiter(writer, input_line, options)
+        write_formatted_with_delimiter(writer, &line, options)
     } else {
         // Whitespace mode requires valid UTF-8
-        match std::str::from_utf8(input_line) {
+        match std::str::from_utf8(&line) {
             Ok(s) => write_formatted_with_whitespace(writer, s, options),
             Err(_) => Err(translate!("numfmt-error-invalid-input")),
         }

tests/by-util/test_numfmt.rs

@@ -1249,3 +1249,24 @@ fn test_empty_delimiter_whitespace_rejection() {
         .fails_with_code(2)
         .stderr_contains("invalid suffix in input");
 }
+
+#[test]
+fn test_null_byte_input() {
+    new_ucmd!()
+        .pipe_in("1000\x00")
+        .succeeds()
+        .stdout_is("1000\n");
+}
+
+#[test]
+fn test_null_byte_input_multiline() {
+    new_ucmd!()
+        .pipe_in("1000\x00\n2000\x00")
+        .succeeds()
+        .stdout_is("1000\n2000\n");
+
+    new_ucmd!()
+        .pipe_in("1000\x002000\n3000")
+        .succeeds()
+        .stdout_is("1000\n3000\n");
+}