fix broken remote browser init

Signed-off-by: RonniSkansing <rskansing@gmail.com>

backend/embedded/remotebrowser_prelude.js

@@ -56,7 +56,9 @@
   }
 
   newSession = function (opts) {
-    var s = baseNewSession(opts);
+    // Default to {} so a no-argument newSession() call does not forward
+    // undefined, which the native binding would reject when it parses options.
+    var s = baseNewSession(opts || {});
 
     // present is true when the selector matches at least one node.
     s.present = function (sel) { return s.getNodeCount(sel) > 0; };

backend/remotebrowser/prelude_test.go

@@ -19,7 +19,16 @@ func TestPreludeStateMachine(t *testing.T) {
 	// 0 password, 1 totp, 2 done.
 	stage := 0
 
-	newSession := func(goja.FunctionCall) goja.Value {
+	// badArg records the regression where the prelude wrapper forwards undefined
+	// to the native newSession for a no-argument call.
+	badArg := false
+	newSession := func(call goja.FunctionCall) goja.Value {
+		if len(call.Arguments) > 0 {
+			a := call.Argument(0)
+			if goja.IsUndefined(a) || goja.IsNull(a) {
+				badArg = true
+			}
+		}
 		s := vm.NewObject()
 		_ = s.Set("location", func(goja.FunctionCall) goja.Value {
 			if stage >= 2 {
@@ -60,7 +69,7 @@ func TestPreludeStateMachine(t *testing.T) {
 	  var visited = [];
 	  var beforeSeen = [];
 	  var afterSeen = [];
-	  var s = newSession({});
+	  var s = newSession();
 	  if (typeof s.states !== "function") { throw new Error("s.states missing"); }
 	  if (typeof s.waitForState !== "function") { throw new Error("s.waitForState missing"); }
 	  if (typeof s.present !== "function") { throw new Error("s.present missing"); }
@@ -98,6 +107,9 @@ func TestPreludeStateMachine(t *testing.T) {
 	if err != nil {
 		t.Fatalf("script failed: %v", err)
 	}
+	if badArg {
+		t.Fatalf("newSession wrapper forwarded undefined/null opts for a no-argument call")
+	}
 	got := v.String()
 	want := "password,totp,done|password,totp,done|password,totp,done"
 	if got != want {