fs: preserve directory timestamps in cpSync fast path

This completes the work started in PR #65540. While the previous PR fixed
directory timestamp preservation for the JavaScript paths, the native C++
fast path (CpSyncCopyDir in src/node_file.cc) used by fs.cpSync when no
filter is provided still failed to preserve directory timestamps.

This commit invokes the existing CopyUtimes helper for both the root
destination directory and all subdirectories after their contents are
recursively copied.

PR-URL: #65678
Signed-off-by: Abhinandan Kumar <abhi128618@gmail.com>

Author: abhi128nandan

src/node_file.cc

@@ -4207,6 +4207,10 @@ static void CpSyncCopyDir(const FunctionCallbackInfo<Value>& args) {
         if (!success) {
           return false;
         }
+        if (preserve_timestamps &&
+            !CopyUtimes(entry_dir_path, dest_file_path, env)) {
+          return false;
+        }
       } else if (dir_entry.is_regular_file()) {
         std::filesystem::copy_file(
             dir_entry.path(), dest_file_path, file_copy_opts, error);
@@ -4231,7 +4235,9 @@ static void CpSyncCopyDir(const FunctionCallbackInfo<Value>& args) {
     return true;
   };
 
-  copy_dir_contents(src_path, dest_path);
+  if (copy_dir_contents(src_path, dest_path) && preserve_timestamps) {
+    CopyUtimes(src_path, dest_path, env);
+  }
 }
 
 BindingData::FilePathIsFileReturnType BindingData::FilePathIsFile(

test/parallel/test-fs-cp-sync-preserve-timestamps-dir.mjs

@@ -1,5 +1,6 @@
-// This tests that cpSync with a filter preserves directory timestamps
-// when preserveTimestamps is true.
+// This tests that cpSync preserves directory timestamps
+// when preserveTimestamps is true, both on the JS fallback path (with filter)
+// and the native fast path (without filter).
 import '../common/index.mjs';
 import { nextdir } from '../common/fs.js';
 import assert from 'node:assert';
@@ -40,3 +41,21 @@ assert.strictEqual(srcDirStat.mtime.getTime(), destDirStat.mtime.getTime());
 const srcRootStat = statSync(src);
 const destRootStat = statSync(dest);
 assert.strictEqual(srcRootStat.mtime.getTime(), destRootStat.mtime.getTime());
+
+// Copy with preserveTimestamps and NO filter (to exercise the native fast path).
+const destFast = nextdir();
+cpSync(src, destFast, {
+  recursive: true,
+  preserveTimestamps: true,
+});
+
+// Verify file timestamps are preserved.
+const destFastFileStat = statSync(join(destFast, 'subdir', 'file.txt'));
+assert.strictEqual(srcFileStat.mtime.getTime(), destFastFileStat.mtime.getTime());
+
+// Verify directory timestamps are preserved.
+const destFastDirStat = statSync(join(destFast, 'subdir'));
+assert.strictEqual(srcDirStat.mtime.getTime(), destFastDirStat.mtime.getTime());
+
+const destFastRootStat = statSync(destFast);
+assert.strictEqual(srcRootStat.mtime.getTime(), destFastRootStat.mtime.getTime());