fs: respect dereference when copy symlink directory

Co-authored-by: Jake Yuesong Li <jake.yuesong@gmail.com>
PR-URL: #54732
Fixes: #54730
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node_file.cc

@@ -3155,7 +3155,9 @@ static void CpSyncCheckPaths(const FunctionCallbackInfo<Value>& args) {
 
   bool dest_exists = !error_code && dest_status.type() !=
                                         std::filesystem::file_type::not_found;
-  bool src_is_dir = src_status.type() == std::filesystem::file_type::directory;
+  bool src_is_dir =
+      (src_status.type() == std::filesystem::file_type::directory) ||
+      (dereference && src_status.type() == std::filesystem::file_type::symlink);
 
   if (!error_code) {
     // Check if src and dest are identical.

test/parallel/test-fs-cp.mjs

@@ -119,6 +119,23 @@ function nextdir() {
 }
 
 
+// It overrides target directory with what symlink points to, when dereference is true.
+{
+  const src = nextdir();
+  const symlink = nextdir();
+  const dest = nextdir();
+  mkdirSync(src, mustNotMutateObjectDeep({ recursive: true }));
+  writeFileSync(join(src, 'foo.js'), 'foo', 'utf8');
+  symlinkSync(src, symlink);
+
+  mkdirSync(dest, mustNotMutateObjectDeep({ recursive: true }));
+
+  cpSync(symlink, dest, mustNotMutateObjectDeep({ dereference: true, recursive: true }));
+  const destStat = lstatSync(dest);
+  assert(!destStat.isSymbolicLink());
+  assertDirEquivalent(src, dest);
+}
+
 // It throws error when verbatimSymlinks is not a boolean.
 {
   const src = './test/fixtures/copy/kitchen-sink';