du: make -l/--count-links work

src/uu/du/src/du.rs

@@ -88,6 +88,7 @@ struct Options {
     separate_dirs: bool,
     one_file_system: bool,
     dereference: Deref,
+    count_links: bool,
     inodes: bool,
     verbose: bool,
 }
@@ -336,6 +337,9 @@ fn du(
 
                             if let Some(inode) = this_stat.inode {
                                 if inodes.contains(&inode) {
+                                    if options.count_links {
+                                        my_stat.inodes += 1;
+                                    }
                                     continue;
                                 }
                                 inodes.insert(inode);
@@ -561,6 +565,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         } else {
             Deref::None
         },
+        count_links: matches.get_flag(options::COUNT_LINKS),
         inodes: matches.get_flag(options::INODES),
         verbose: matches.get_flag(options::VERBOSE),
     };

tests/by-util/test_du.rs

@@ -441,6 +441,33 @@ fn test_du_inodes() {
     }
 }
 
+#[test]
+fn test_du_inodes_with_count_links() {
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("dir");
+    at.touch("dir/file");
+    at.hard_link("dir/file", "dir/hard_link_a");
+    at.hard_link("dir/file", "dir/hard_link_b");
+
+    // ensure the hard links are not counted without --count-links
+    ts.ucmd()
+        .arg("--inodes")
+        .arg("dir")
+        .succeeds()
+        .stdout_is("2\tdir\n");
+
+    for arg in ["-l", "--count-links"] {
+        ts.ucmd()
+            .arg("--inodes")
+            .arg(arg)
+            .arg("dir")
+            .succeeds()
+            .stdout_is("4\tdir\n");
+    }
+}
+
 #[test]
 fn test_du_h_flag_empty_file() {
     new_ucmd!()