From 2de58cd3772fbe9138db9368e0015dcc063f8cbf Mon Sep 17 00:00:00 2001
From: Marko Lahma <marko.lahma@gmail.com>
Date: Sat, 15 Jun 2024 20:58:50 +0300
Subject: [PATCH] Support creating NamespaceReference against empty namespace
 (#1892)

---
 Jint.Tests/Runtime/Domain/Shape.cs         |  5 +++++
 Jint.Tests/Runtime/InteropTests.cs         | 16 ++++++++++++++++
 Jint/Options.cs                            |  3 +--
 Jint/Runtime/Interop/NamespaceReference.cs | 15 ++++++++++-----
 4 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/Jint.Tests/Runtime/Domain/Shape.cs b/Jint.Tests/Runtime/Domain/Shape.cs
index 40cbd30781..2c053bbe83 100644
--- a/Jint.Tests/Runtime/Domain/Shape.cs
+++ b/Jint.Tests/Runtime/Domain/Shape.cs
@@ -1,5 +1,10 @@
 using Jint.Tests.Runtime.Domain;
 
+public class ShapeWithoutNameSpace : Shapes.Shape
+{
+    public override double Perimeter() => 42;
+}
+
 namespace Shapes
 {
     public abstract class Shape
diff --git a/Jint.Tests/Runtime/InteropTests.cs b/Jint.Tests/Runtime/InteropTests.cs
index 2c3a062524..ff32087f26 100644
--- a/Jint.Tests/Runtime/InteropTests.cs
+++ b/Jint.Tests/Runtime/InteropTests.cs
@@ -1302,6 +1302,22 @@ public void ShouldImportNamespace()
             ");
         }
 
+        [Fact]
+        public void ShouldImportEmptyNamespace()
+        {
+            RunTest("""
+                var nullSpace = importNamespace(null);
+                var c1 = new nullSpace.ShapeWithoutNameSpace();
+                assert(c1.Perimeter() === 42);
+                var undefinedSpace = importNamespace(undefined);
+                var c2 = new undefinedSpace.ShapeWithoutNameSpace();
+                assert(c2.Perimeter() === 42);
+                var defaultSpace = importNamespace();
+                var c3 = new defaultSpace.ShapeWithoutNameSpace();
+                assert(c3.Perimeter() === 42);
+            """);
+        }
+
         [Fact]
         public void ShouldConstructReferenceTypeWithParameters()
         {
diff --git a/Jint/Options.cs b/Jint/Options.cs
index 9eb1d6584e..b0775768e3 100644
--- a/Jint/Options.cs
+++ b/Jint/Options.cs
@@ -126,8 +126,7 @@ internal void Apply(Engine engine)
             engine.Realm.GlobalObject.SetProperty("importNamespace", new PropertyDescriptor(new ClrFunction(
                     engine,
                     "importNamespace",
-                    (thisObj, arguments) =>
-                        new NamespaceReference(engine, TypeConverter.ToString(arguments.At(0)))),
+                    (_, arguments) => new NamespaceReference(engine, arguments.At(0).IsNullOrUndefined() ? null : TypeConverter.ToString(arguments.At(0)))),
                 PropertyFlag.AllForbidden));
 
             engine.Realm.GlobalObject.SetProperty("clrHelper", new PropertyDescriptor(ObjectWrapper.Create(engine, new ClrHelper(Interop)), PropertyFlag.AllForbidden));
diff --git a/Jint/Runtime/Interop/NamespaceReference.cs b/Jint/Runtime/Interop/NamespaceReference.cs
index efaab337f8..c14c898bc8 100644
--- a/Jint/Runtime/Interop/NamespaceReference.cs
+++ b/Jint/Runtime/Interop/NamespaceReference.cs
@@ -18,9 +18,9 @@ namespace Jint.Runtime.Interop
     [RequiresUnreferencedCode("Dynamic loading")]
     public class NamespaceReference : ObjectInstance, ICallable
     {
-        private readonly string _path;
+        private readonly string? _path;
 
-        public NamespaceReference(Engine engine, string path) : base(engine)
+        public NamespaceReference(Engine engine, string? path) : base(engine)
         {
             _path = path;
         }
@@ -75,7 +75,9 @@ JsValue ICallable.Call(JsValue thisObject, JsValue[] arguments)
 
         public override JsValue Get(JsValue property, JsValue receiver)
         {
-            var newPath = _path + "." + property;
+            var newPath = string.IsNullOrEmpty(_path)
+                ? property.ToString()
+                : $"{_path}.{property}";
 
             return GetPath(newPath);
         }
@@ -123,8 +125,11 @@ public JsValue GetPath(string path)
                 }
 
                 var lastPeriodPos = path.LastIndexOf('.');
-                var trimPath = path.Substring(0, lastPeriodPos);
-                type = GetType(assembly, trimPath);
+                if (lastPeriodPos != -1)
+                {
+                    var trimPath = path.Substring(0, lastPeriodPos);
+                    type = GetType(assembly, trimPath);
+                }
                 if (type != null)
                 {
                     foreach (Type nType in GetAllNestedTypes(type))