fs: check subdir correctly in cpSync

src/node_file.cc

@@ -3192,8 +3192,12 @@ static void CpSyncCheckPaths(const FunctionCallbackInfo<Value>& args) {
  }
 
  std::string dest_path_str = dest_path.string();
+ std::string src_path_str = src_path.string();
+ if (!src_path_str.ends_with(std::filesystem::path::preferred_separator)) {
+ src_path_str += std::filesystem::path::preferred_separator;
+ }
  // Check if dest_path is a subdirectory of src_path.
- if (src_is_dir && dest_path_str.starts_with(src_path.string())) {
+ if (src_is_dir && dest_path_str.starts_with(src_path_str)) {
  std::string message = "Cannot copy " + src_path.string() +
  " to a subdirectory of self " + dest_path.string();
  return THROW_ERR_FS_CP_EINVAL(env, message.c_str());

test/parallel/test-fs-cp.mjs

@@ -24,8 +24,8 @@ import tmpdir from '../common/tmpdir.js';
 tmpdir.refresh();
 
 let dirc = 0;
-function nextdir() {
- return tmpdir.resolve(`copy_${++dirc}`);
+function nextdir(dirname) {
+ return tmpdir.resolve(dirname || `copy_${++dirc}`);
 }
 
 // Synchronous implementation of copy.
@@ -312,6 +312,45 @@ function nextdir() {
  );
 }
 
+// It must not throw error if attempt is made to copy to dest
+// directory with same prefix as src directory
+// regression test for https://github.com/nodejs/node/issues/54285
+{
+ const src = nextdir('prefix');
+ const dest = nextdir('prefix-a');
+ mkdirSync(src);
+ mkdirSync(dest);
+ cpSync(src, dest, mustNotMutateObjectDeep({ recursive: true }));
+}
+
+// It must not throw error if attempt is made to copy to dest
+// directory if the parent of dest has same prefix as src directory
+// regression test for https://github.com/nodejs/node/issues/54285
+{
+ const src = nextdir('aa');
+ const destParent = nextdir('aaa');
+ const dest = nextdir('aaa/aabb');
+ mkdirSync(src);
+ mkdirSync(destParent);
+ mkdirSync(dest);
+ cpSync(src, dest, mustNotMutateObjectDeep({ recursive: true }));
+}
+
+// It throws error if attempt is made to copy src to dest
+// when src is parent directory of the parent of dest
+{
+ const src = nextdir('a');
+ const destParent = nextdir('a/b');
+ const dest = nextdir('a/b/c');
+ mkdirSync(src);
+ mkdirSync(destParent);
+ mkdirSync(dest);
+ assert.throws(
+ () => cpSync(src, dest, mustNotMutateObjectDeep({ recursive: true })),
+ { code: 'ERR_FS_CP_EINVAL' },
+ );
+}
+
 // It throws error if attempt is made to copy to subdirectory of self.
 {
  const src = './test/fixtures/copy/kitchen-sink';