sort: compare strings before comparing hashes

Since lines that compare equal should be sorted together, we need to first
compare the lines (taking settings into account). Only if they do not compare
equal we should compare the hashes.

src/uu/sort/src/sort.rs

@@ -1398,7 +1398,22 @@ fn compare_by<'a>(
         let settings = &selector.settings;
 
         let cmp: Ordering = match settings.mode {
-            SortMode::Random => random_shuffle(a_str, b_str, &global_settings.salt.unwrap()),
+            SortMode::Random => {
+                // check if the two strings are equal
+                if custom_str_cmp(
+                    a_str,
+                    b_str,
+                    settings.ignore_non_printing,
+                    settings.dictionary_order,
+                    settings.ignore_case,
+                ) == Ordering::Equal
+                {
+                    Ordering::Equal
+                } else {
+                    // Only if they are not equal compare by the hash
+                    random_shuffle(a_str, b_str, &global_settings.salt.unwrap())
+                }
+            }
             SortMode::Numeric => {
                 let a_num_info = &a_line_data.num_infos
                     [a.index * global_settings.precomputed.num_infos_per_line + num_info_index];

tests/by-util/test_sort.rs

@@ -235,6 +235,16 @@ fn test_random_shuffle_two_runs_not_the_same() {
     }
 }
 
+#[test]
+fn test_random_ignore_case() {
+    let input = "ABC\nABc\nAbC\nAbc\naBC\naBc\nabC\nabc\n";
+    new_ucmd!()
+        .args(&["-fR"])
+        .pipe_in(input)
+        .succeeds()
+        .stdout_is(input);
+}
+
 #[test]
 fn test_numeric_floats_and_ints() {
     test_helper(