Generate error when accessing string index of primitive

Author: mikebridge

Liquid.NET.Tests/Constants/MissingValueTests.cs

@@ -1,8 +1,5 @@
 using System;
-using System.Collections.Generic;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Liquid.NET.Constants;
 using NUnit.Framework;
 
@@ -55,6 +52,8 @@ public void It_Should_Display_An_Error_When_Dereferencing_Empty_Array(String var
 
         }
 
+
+
         [Test]
         public void It_Should_Display_Error_When_Dereferencing_Array_With_Non_Int()
         {
@@ -73,6 +72,26 @@ public void It_Should_Display_Error_When_Dereferencing_Array_With_Non_Int()
 
         }
 
+        [Test]
+        public void It_Should_Display_Error_When_Dereferencing_Primitive_With_Index()
+        {
+            // Arrange
+            ITemplateContext ctx = new TemplateContext()
+                .ErrorWhenValueMissing();
+            ctx.DefineLocalVariable("e", LiquidString.Create("Hello"));
+
+            // Act
+            var template = LiquidTemplate.Create("Result : {{ e.x }}");
+            var result = template.LiquidTemplate.Render(ctx);
+
+            Assert.That(result.HasRenderingErrors, Is.True);
+            var errorMessage = String.Join(",", result.RenderingErrors.Select(x => x.Message));
+            // Assert
+            Assert.That(errorMessage, Is.StringContaining("invalid string index: 'x'"));
+
+        }
+
+
         [Test]
         [TestCase("x")]
         [TestCase("e[1]")]

Liquid.NET/src/Constants/IndexDereferencer.cs

@@ -147,14 +147,18 @@ private LiquidExpressionResult DoLookup(ITemplateContext ctx, LiquidString str,
             }
             else
             {
-                var maybeIndexResult = ValueCaster.Cast<ILiquidValue, LiquidNumeric>(indexProperty);
-                if (maybeIndexResult.IsError || !maybeIndexResult.SuccessResult.HasValue)
-                {
-                    return LiquidExpressionResult.Error("invalid array index: " + propertyNameString);
+                //var maybeIndexResult = ValueCaster.Cast<ILiquidValue, LiquidNumeric>(indexProperty);
+                var numericIndexProperty = indexProperty as LiquidNumeric;
+                
+                if (numericIndexProperty == null)
+                {                  
+                    return ctx.Options.ErrorWhenValueMissing ? 
+                        LiquidExpressionResult.Error("invalid string index: '" + propertyNameString + "'") : 
+                        LiquidExpressionResult.Success(new None<ILiquidValue>());
                 }
                 else
                 {
-                    index = maybeIndexResult.SuccessValue<LiquidNumeric>().IntValue;
+                    index = numericIndexProperty.IntValue;
                 }
             }