fs: throw realpathSync.native errors in JS

PR-URL: https://github.com/nodejs/node/pull/18871
Refs: https://github.com/nodejs/node/issues/18106
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/fs.js

@@ -1649,7 +1649,10 @@ fs.realpathSync.native = function(path, options) {
   options = getOptions(options, {});
   path = getPathFromURL(path);
   validatePath(path);
-  return binding.realpath(path, options.encoding);
+  const ctx = { path };
+  const result = binding.realpath(path, options.encoding, undefined, ctx);
+  handleErrorFromBinding(ctx);
+  return result;
 };
 
 

src/node_file.cc

@@ -1047,20 +1047,30 @@ static void MKDir(const FunctionCallbackInfo<Value>& args) {
 }
 
 static void RealPath(const FunctionCallbackInfo<Value>& args) {
-  CHECK_GE(args.Length(), 2);
   Environment* env = Environment::GetCurrent(args);
+
+  const int argc = args.Length();
+  CHECK_GE(argc, 3);
+
   BufferValue path(env->isolate(), args[0]);
   CHECK_NE(*path, nullptr);
 
   const enum encoding encoding = ParseEncoding(env->isolate(), args[1], UTF8);
 
   FSReqBase* req_wrap = GetReqWrap(env, args[2]);
-  if (req_wrap != nullptr) {
+  if (req_wrap != nullptr) {  // realpath(path, encoding, req)
     AsyncCall(env, req_wrap, args, "realpath", encoding, AfterStringPtr,
               uv_fs_realpath, *path);
-  } else {
-    SYNC_CALL(realpath, *path, *path);
-    const char* link_path = static_cast<const char*>(SYNC_REQ.ptr);
+  } else {  // realpath(path, encoding, undefined, ctx)
+    CHECK_EQ(argc, 4);
+    fs_req_wrap req_wrap;
+    int err = SyncCall(env, args[3], &req_wrap, "realpath",
+                       uv_fs_realpath, *path);
+    if (err < 0) {
+      return;  // syscall failed, no need to continue, error info is in ctx
+    }
+
+    const char* link_path = static_cast<const char*>(req_wrap.req.ptr);
 
     Local<Value> error;
     MaybeLocal<Value> rc = StringBytes::Encode(env->isolate(),
@@ -1068,9 +1078,11 @@ static void RealPath(const FunctionCallbackInfo<Value>& args) {
                                                encoding,
                                                &error);
     if (rc.IsEmpty()) {
-      env->isolate()->ThrowException(error);
+      Local<Object> ctx = args[3].As<Object>();
+      ctx->Set(env->context(), env->error_string(), error).FromJust();
       return;
     }
+
     args.GetReturnValue().Set(rc.ToLocalChecked());
   }
 }

test/parallel/test-fs-error-messages.js

@@ -125,6 +125,27 @@ function re(literals, ...values) {
   );
 }
 
+// native realpath
+{
+  const validateError = (err) => {
+    assert.strictEqual(nonexistentFile, err.path);
+    assert.strictEqual(
+      err.message,
+      `ENOENT: no such file or directory, realpath '${nonexistentFile}'`);
+    assert.strictEqual(err.errno, uv.UV_ENOENT);
+    assert.strictEqual(err.code, 'ENOENT');
+    assert.strictEqual(err.syscall, 'realpath');
+    return true;
+  };
+
+  fs.realpath.native(nonexistentFile, common.mustCall(validateError));
+
+  assert.throws(
+    () => fs.realpathSync.native(nonexistentFile),
+    validateError
+  );
+}
+
 // readlink
 {
   const validateError = (err) => {