fs: expose realpath(3) bindings

Make the `uv_fs_realpath()` binding (which calls the libc `realpath()`
on UNIX and `GetFinalPathNameByHandle()` on Windows) available as the
`fs.realpath.native()` and `fs.realpathSync.native()` functions.

The binding was already available as `process.binding('fs').realpath`
but was not exposed or tested - and partly broken as a result.

Fixes: https://github.com/nodejs/node/issues/8715
PR-URL: https://github.com/nodejs/node/pull/15776
Refs: https://github.com/nodejs/node/pull/7899
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/test/parallel/test-fs-realpath-native.js b/test/parallel/test-fs-realpath-native.js
new file mode 100644
index 0000000000..43d6b8ca80
--- /dev/null
+++ b/test/parallel/test-fs-realpath-native.js
@@ -0,0 +1,12 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const fs = require('fs');
+
+if (!common.isOSX) common.skip('MacOS-only test.');
+
+assert.strictEqual(fs.realpathSync.native('/users'), '/Users');
+fs.realpath.native('/users', common.mustCall((err, res) => {
+  assert.ifError(err);
+  assert.strictEqual(res, '/Users');
+}));