From a96ed2de96e34929d6c1ac7f9fc690e16dee1643 Mon Sep 17 00:00:00 2001
From: Wilfred Hughes <me@wilfred.me.uk>
Date: Wed, 22 Oct 2025 00:49:42 +0100
Subject: [PATCH] Improve binary change descriptions

---
 src/main.rs  | 30 +++++++++++++++++++++++++-----
 tests/cli.rs |  4 ++--
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 14f97d745..32abfa12b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -974,11 +974,31 @@ fn print_diff_result(display_options: &DisplayOptions, summary: &DiffResult) {
                 match summary.has_byte_changes {
                     Some((lhs_len, rhs_len)) => {
                         let format_options = FormatSizeOptions::from(BINARY).decimal_places(1);
-                        println!(
-                            "Binary contents changed (old: {}, new: {}).\n",
-                            &format_size(lhs_len, format_options),
-                            &format_size(rhs_len, format_options),
-                        )
+
+                        if lhs_len == 0 {
+                            // Strictly speaking this is wrong:
+                            // previously we may have had an empty but
+                            // existent file. In that case, it's a
+                            // file modification instead of a file
+                            // creation.
+                            //
+                            // TODO: Fix this pedantic case.
+                            println!(
+                                "Binary file added ({}).\n",
+                                &format_size(rhs_len, format_options),
+                            )
+                        } else if rhs_len == 0 {
+                            println!(
+                                "Binary file removed ({}).\n",
+                                &format_size(lhs_len, format_options),
+                            )
+                        } else {
+                            println!(
+                                "Binary file modified (old: {}, new: {}).\n",
+                                &format_size(lhs_len, format_options),
+                                &format_size(rhs_len, format_options),
+                            )
+                        }
                     }
                     None => println!("No changes.\n"),
                 }
diff --git a/tests/cli.rs b/tests/cli.rs
index ebbe3aa0f..90c3025df 100644
--- a/tests/cli.rs
+++ b/tests/cli.rs
@@ -57,7 +57,7 @@ fn binary_changed() {
         .arg("img/logo.png")
         .arg("/dev/null");
 
-    let predicate_fn = predicate::str::contains("Binary contents changed");
+    let predicate_fn = predicate::str::contains("Binary file removed");
     cmd.assert().stdout(predicate_fn);
 }
 
@@ -68,7 +68,7 @@ fn binary_override() {
     cmd.arg("--override-binary=*.js")
         .arg("sample_files/simple_1.js")
         .arg("sample_files/simple_2.js");
-    let predicate_fn = predicate::str::contains("Binary contents changed");
+    let predicate_fn = predicate::str::contains("Binary file modified");
     cmd.assert().stdout(predicate_fn);
 }