cp: replace distinct symlinks when creating hard links

src/uu/cp/src/cp.rs

@@ -2578,14 +2578,18 @@ fn handle_copy_mode(
                 }
                 force = options.overwrite == OverwriteMode::Clobber(ClobberMode::Force);
             }
+            // Check after backup handling, which may have moved the destination away.
+            let replace_symlink = !options.dereference(source_in_command_line)
+                && source_metadata.file_type().is_symlink()
+                && dest.is_symlink();
             let src = if options.dereference(source_in_command_line) && source.is_symlink() {
                 canonicalize(source, MissingHandling::Missing, ResolveMode::Physical).unwrap()
             } else {
                 source.to_path_buf()
             };
             // Replace atomically rather than unlinking first: the gap would
             // let another user claim `dest` under a name the caller trusts.
-            if force {
+            if force || replace_symlink {
                 replace_link(&src, dest, false)
             } else {
                 fs::hard_link(&src, dest)
@@ -2596,6 +2600,12 @@ fn handle_copy_mode(
                     translate!("cp-error-cannot-create-hard-link", "dest" => get_filename(dest).unwrap_or("?").quote(), "source" => get_filename(source).unwrap_or("?").quote())
                 )
             })?;
+            if replace_symlink && options.verbose {
+                println!(
+                    "{}",
+                    translate!("cp-verbose-removed", "path" => dest.quote())
+                );
+            }
         }
         CopyMode::Copy => {
             copy_helper(
@@ -2853,7 +2863,12 @@ fn copy_file(
                 OverwriteMode::Clobber(ClobberMode::RemoveDestination)
             ))
     {
-        if paths_refer_to_same_file(source, dest, true) && options.copy_mode == CopyMode::Link {
+        // Distinct symlinks can share a target without being the same link under -P.
+        let dereference_links =
+            options.dereference(source_in_command_line) || !source_is_symlink || !dest_is_symlink;
+        if options.copy_mode == CopyMode::Link
+            && paths_refer_to_same_file(source, dest, dereference_links)
+        {
             if source_is_symlink {
                 if !dest_is_symlink {
                     return Ok(());

tests/by-util/test_cp.rs

@@ -9890,3 +9890,59 @@ fn test_progressbar_inexistent_source() {
         .fails_with_code(1)
         .stderr_contains("cp: cannot stat 'inexistent1': No such file or directory");
 }
+
+#[cfg(all(unix, not(target_os = "android")))] // Android denies hard links in the test directory.
+#[rstest]
+fn test_cp_hardlink_replaces_distinct_symlink(
+    #[values("file", "hop")] target: &str,
+    #[values(false, true)] backup: bool,
+) {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.write("file", "keep me");
+    at.symlink_file("file", "source");
+    at.symlink_file("file", "hop");
+    at.symlink_file(target, "dest");
+    let dest_inode = at.symlink_metadata("dest").ino();
+
+    let expected = if backup {
+        ucmd.arg("--backup=simple");
+        "'source' -> 'dest'\n"
+    } else {
+        "removed 'dest'\n'source' -> 'dest'\n"
+    };
+
+    ucmd.args(&["--link", "--no-dereference", "--verbose", "source", "dest"])
+        .succeeds()
+        .stdout_only(expected);
+
+    assert_eq!(at.resolve_link("dest"), "file");
+    assert_eq!(
+        at.symlink_metadata("source").ino(),
+        at.symlink_metadata("dest").ino()
+    );
+    assert_eq!(at.read("file"), "keep me");
+    if backup {
+        assert_eq!(at.resolve_link("dest~"), target);
+        assert_eq!(at.symlink_metadata("dest~").ino(), dest_inode);
+    }
+}
+
+#[cfg(all(unix, not(target_os = "android")))] // Android denies hard links in the test directory.
+#[rstest]
+fn test_cp_hardlink_keeps_existing_symlink(#[values(false, true)] dangling: bool) {
+    let (at, mut ucmd) = at_and_ucmd!();
+    if !dangling {
+        at.write("file", "keep me");
+    }
+    at.symlink_file("file", "source");
+    at.hard_link("source", "dest");
+    let inode = at.symlink_metadata("dest").ino();
+
+    ucmd.args(&["--link", "--no-dereference", "--verbose", "source", "dest"])
+        .succeeds()
+        .no_output();
+
+    assert_eq!(at.resolve_link("dest"), "file");
+    assert_eq!(at.symlink_metadata("dest").ino(), inode);
+    assert_eq!(at.symlink_metadata("source").ino(), inode);
+}