From fc180591aac039f38592a2b47368cb65c9878460 Mon Sep 17 00:00:00 2001
From: Shaurya Kesarwani <kesar.shaurya@gmail.com>
Date: Mon, 26 Oct 2026 12:10:53 +0530
Subject: [PATCH] cmp: don't pad the printed bytes when the second byte is
 non-ASCII

With -b, the character column after the first byte was padded to two
columns whenever the second byte was 0x7F or higher, so a printable
first byte got an extra space ("141 a  303 M-C"). GNU cmp prints the
two bytes separated by a single space in every case.
---
 src/cmp.rs                |  3 +--
 tests/by-util/test_cmp.rs | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/cmp.rs b/src/cmp.rs
index 3ff716f..dc212d2 100644
--- a/src/cmp.rs
+++ b/src/cmp.rs
@@ -703,9 +703,8 @@ fn report_difference(
         at_line
     );
     if params.print_bytes {
-        let char_width = if to_byte >= 0x7F { 2 } else { 1 };
         print!(
-            " is {:>3o} {:char_width$} {:>3o} {:char_width$}",
+            " is {:>3o} {} {:>3o} {}",
             from_byte,
             format_visible_byte(from_byte),
             to_byte,
diff --git a/tests/by-util/test_cmp.rs b/tests/by-util/test_cmp.rs
index 0053a46..a36d16a 100644
--- a/tests/by-util/test_cmp.rs
+++ b/tests/by-util/test_cmp.rs
@@ -452,6 +452,34 @@ fn cmp_skip() -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
+#[test]
+fn cmp_print_bytes_high_byte() -> Result<(), Box<dyn std::error::Error>> {
+    let tmp_dir = tempdir()?;
+
+    let a_path = tmp_dir.path().join("a");
+    let mut a = File::create(&a_path).unwrap();
+    a.write_all(b"a").unwrap();
+
+    let b_path = tmp_dir.path().join("b");
+    let mut b = File::create(&b_path).unwrap();
+    b.write_all(&[0xC3]).unwrap();
+
+    // GNU cmp does not pad the printed bytes, whatever the second byte is.
+    let mut cmd = cargo_bin_cmd!("diffutils");
+    cmd.arg("cmp");
+    cmd.arg("-b");
+    cmd.arg(&a_path).arg(&b_path);
+    cmd.assert()
+        .code(predicate::eq(1))
+        .failure()
+        .stderr(predicate::str::is_empty())
+        .stdout(predicate::str::ends_with(
+            " differ: byte 1, line 1 is 141 a 303 M-C\n",
+        ));
+
+    Ok(())
+}
+
 #[test]
 fn cmp_binary() -> Result<(), Box<dyn std::error::Error>> {
     let tmp_dir = tempdir()?;