uucore: version_cmp: compare endings when stems tie as versions

src/uucore/src/lib/features/version_cmp.rs

@@ -103,8 +103,13 @@ pub fn version_cmp(mut a: &[u8], mut b: &[u8]) -> Ordering {
 
     // Try to strip file extensions
     let (mut a, mut b) = match (remove_file_ending(a), remove_file_ending(b)) {
-        (a_stripped, b_stripped) if a_stripped == b_stripped => {
+        (a_stripped, b_stripped)
+            if a_stripped == b_stripped
+                || ((a_stripped, b_stripped) != (a, b)
+                    && version_cmp(a_stripped, b_stripped) == Ordering::Equal) =>
+        {
             // If both would be the same after stripping file extensions, don't strip them.
+            // "Same" means equal as versions, not only as bytes (`1.00` and `1.0`).
             (a, b)
         }
         stripped => stripped,
@@ -368,4 +373,25 @@ mod tests {
             "NULL bytes are handled comparison"
         );
     }
+
+    #[test]
+    fn test_version_cmp_endings_decide_version_equal_stems() {
+        // The stems only differ in leading zeros, so they tie as versions and the
+        // endings must decide. Equal here makes `sort -V -u` drop one of the lines.
+        for (a, b) in [
+            (&b"tool-1.00.txt"[..], &b"tool-1.0.exe"[..]),
+            (b"tool-1.00", b"tool-1.0.exe"),
+            (b"01.txt", b"1.log"),
+            (b"setup0.txt", b"setup.exe"),
+            (b"lib-2.010.so", b"lib-2.10.a"),
+            (b"app-1.00.zip", b"app-1.0.tar.gz"),
+        ] {
+            assert_ne!(version_cmp(a, b), Ordering::Equal);
+            assert_eq!(version_cmp(a, b), version_cmp(b, a).reverse());
+        }
+        assert_eq!(
+            version_cmp(b"tool-1.00.txt", b"tool-1.0.exe"),
+            Ordering::Greater
+        );
+    }
 }

tests/by-util/test_sort.rs

@@ -302,6 +302,15 @@ fn test_version_sort_unstable() {
         .stdout_is("0.1\n0.002\n0.02\n0.2\n0.3\n");
 }
 
+#[test]
+fn test_version_sort_unique_keeps_different_endings() {
+    new_ucmd!()
+        .args(&["-V", "-u"])
+        .pipe_in("tool-1.00.txt\ntool-1.0.exe\n")
+        .succeeds()
+        .stdout_is("tool-1.0.exe\ntool-1.00.txt\n");
+}
+
 #[test]
 fn test_version_sort_stable() {
     new_ucmd!()