From 4eecccbdd4b9b3192de256e7e8894d42fa853294 Mon Sep 17 00:00:00 2001
From: Marko Lahma <marko.lahma@gmail.com>
Date: Thu, 27 Jun 2024 08:59:19 +0300
Subject: [PATCH] Add interop option ThrowOnUnresolvedMember (#1904)

---
 .../Runtime/InteropTests.MemberAccess.cs      | 24 ++++++++++++++++++-
 Jint/Options.cs                               |  5 ++++
 Jint/Runtime/Interop/TypeResolver.cs          |  5 ++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/Jint.Tests/Runtime/InteropTests.MemberAccess.cs b/Jint.Tests/Runtime/InteropTests.MemberAccess.cs
index 88e7174ef8..f78d77d7f8 100644
--- a/Jint.Tests/Runtime/InteropTests.MemberAccess.cs
+++ b/Jint.Tests/Runtime/InteropTests.MemberAccess.cs
@@ -239,6 +239,8 @@ public TValue this[string key]
 
         public class ClassWithData
         {
+            public int Age => 42;
+
             public DataType Data { get; set; }
 
             public class DataType
@@ -253,10 +255,30 @@ public void NewTypedObjectFromUntypedInitializerShouldBeMapped()
             var engine = new Engine();
 
             engine.SetValue("obj", new ClassWithData());
-            engine.Execute(@"obj.Data = { Value: '123' };");
+            engine.Execute("obj.Data = { Value: '123' };");
             var obj = engine.Evaluate("obj").ToObject() as ClassWithData;
 
             Assert.Equal("123", obj?.Data.Value);
         }
+
+        [Fact]
+        public void CanConfigureStrictAccess()
+        {
+            var engine = new Engine();
+
+            engine.SetValue("obj", new ClassWithData());
+            engine.Evaluate("obj.Age").AsNumber().Should().Be(42);
+            engine.Evaluate("obj.AgeMissing").Should().Be(JsValue.Undefined);
+
+            engine = new Engine(options =>
+            {
+                options.Interop.ThrowOnUnresolvedMember = true;
+            });
+
+            engine.SetValue("obj", new ClassWithData());
+            engine.Evaluate("obj.Age").AsNumber().Should().Be(42);
+
+            engine.Invoking(e => e.Evaluate("obj.AgeMissing")).Should().Throw<MissingMemberException>();
+        }
     }
 }
diff --git a/Jint/Options.cs b/Jint/Options.cs
index b0775768e3..9b9bca7650 100644
--- a/Jint/Options.cs
+++ b/Jint/Options.cs
@@ -359,6 +359,11 @@ public class InteropOptions
         /// Should the Array prototype be attached instead of Object prototype to the wrapped interop objects when type looks suitable. Defaults to true.
         /// </summary>
         public bool AttachArrayPrototype { get; set; } = true;
+
+        /// <summary>
+        /// Whether the engine should throw an error when a member is not found on a CLR object. Defaults to false.
+        /// </summary>
+        public bool ThrowOnUnresolvedMember { get; set; }
     }
 
     public class ConstraintOptions
diff --git a/Jint/Runtime/Interop/TypeResolver.cs b/Jint/Runtime/Interop/TypeResolver.cs
index b8f88ff9a7..2fed2aa082 100644
--- a/Jint/Runtime/Interop/TypeResolver.cs
+++ b/Jint/Runtime/Interop/TypeResolver.cs
@@ -262,6 +262,11 @@ private ReflectionAccessor ResolvePropertyDescriptorFactory(
                 }
             }
 
+            if (engine.Options.Interop.ThrowOnUnresolvedMember)
+            {
+                throw new MissingMemberException($"Cannot access property '{memberName}' on type '{type.FullName}");
+            }
+
             return ConstantValueAccessor.NullAccessor;
         }