cp: cp -P hardlink-to-symlink hardlink-to-same-symlink should noop

Author: dan-hipschman

src/uu/cp/src/cp.rs

@@ -2304,7 +2304,7 @@ fn copy_file(
         }
         handle_existing_dest(source, dest, options, source_in_command_line, copied_files)?;
         if are_hardlinks_to_same_file(source, dest) {
-            if options.copy_mode == CopyMode::Copy && options.backup != BackupMode::NoBackup {
+            if options.copy_mode == CopyMode::Copy {
                 return Ok(());
             }
             if options.copy_mode == CopyMode::Link && (!source_is_symlink || !dest_is_symlink) {

tests/by-util/test_cp.rs

@@ -4675,6 +4675,7 @@ fn test_cp_no_dereference_attributes_only_with_symlink() {
 /// contains the test for cp when the source and destination points to the same file
 mod same_file {
 
+    use std::os::unix::fs::MetadataExt;
     use uutests::util::TestScenario;
     use uutests::util_name;
 
@@ -5594,6 +5595,26 @@ mod same_file {
         assert_eq!(FILE_NAME, at.resolve_link(hardlink_to_symlink));
         assert_eq!(at.read(FILE_NAME), CONTENTS);
     }
+
+    #[test]
+    fn test_hardlink_of_symlink_to_hardlink_of_same_symlink_with_option_no_deref() {
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+        let hardlink1 = "hardlink_to_symlink_1";
+        let hardlink2 = "hardlink_to_symlink_2";
+        at.write(FILE_NAME, CONTENTS);
+        at.symlink_file(FILE_NAME, SYMLINK_NAME);
+        at.hard_link(SYMLINK_NAME, hardlink1);
+        at.hard_link(SYMLINK_NAME, hardlink2);
+        let ino = at.symlink_metadata(hardlink1).ino();
+        assert_eq!(ino, at.symlink_metadata(hardlink2).ino()); // Sanity check
+        scene.ucmd().args(&["-P", hardlink1, hardlink2]).succeeds();
+        assert!(at.file_exists(FILE_NAME));
+        assert!(at.symlink_exists(SYMLINK_NAME));
+        // If hardlink a and b point to the same symlink, then cp a b doesn't create a new file
+        assert_eq!(ino, at.symlink_metadata(hardlink1).ino());
+        assert_eq!(ino, at.symlink_metadata(hardlink2).ino());
+    }
 }
 
 // the following tests are for how the cp should behave when the source is a symlink