Fix Source Gen List of Lists for CBOR (#10)

Author: drasticactions

src/CarpaNet.SourceGen/Generation/CborContextGenerator.cs

@@ -604,6 +604,12 @@ private static string GetArrayConverterExpression(
                 return ListConverterRef(refType, CborTypeInfoRef(refType));
             }
 
+            if (refKind == LexiconTypeKind.Array)
+            {
+                var innerConverter = GetConverterExpressionForArrayRef(items.Ref!, currentNsid, registry);
+                return ListConverterRef(refType, innerConverter);
+            }
+
             var converter = GetPrimitiveConverterForRef(items.Ref!, currentNsid, registry);
             return ListConverterRef(refType, converter);
         }

tests/CarpaNet.UnitTests/Generation/CborContextGeneratorTests.cs

@@ -0,0 +1,67 @@
+using CarpaNet.Generation;
+using CarpaNet.Models;
+using CarpaNet.Utilities;
+
+using Xunit;
+
+namespace CarpaNet.UnitTests.Generation;
+
+public class CborContextGeneratorTests
+{
+    [Fact]
+    public void ArrayOfArrayRef_UsesListConverterNotStringConverter()
+    {
+        // Arrange: reproduce the MebiByte pattern where "transform" is an array
+        // of "transformRow" refs, and "transformRow" is itself an array of strings.
+        // Without the fix, the inner List<string> element gets a StringCborConverter
+        // instead of a CborListTypeInfo<string>.
+        var registry = new TypeRegistry();
+        var doc = new LexiconDocument
+        {
+            Id = "test.nested.array",
+            Defs = new Dictionary<string, LexiconDefinition>
+            {
+                ["transformRow"] = new LexiconDefinition
+                {
+                    Type = "array",
+                    Items = new LexiconDefinition { Type = "string" },
+                },
+                ["main"] = new LexiconDefinition
+                {
+                    Type = "object",
+                    Properties = new Dictionary<string, LexiconDefinition>
+                    {
+                        ["transform"] = new LexiconDefinition
+                        {
+                            Type = "array",
+                            Items = new LexiconDefinition
+                            {
+                                Type = "ref",
+                                Ref = "#transformRow",
+                            },
+                        },
+                    },
+                },
+            },
+        };
+        registry.RegisterDocument(doc);
+
+        var sb = new SourceBuilder();
+        var options = new GeneratorOptions();
+        var mainDef = doc.Defs["main"];
+
+        // Act
+        CborContextGenerator.GenerateCborTypeInfo(
+            sb, "TestNested.Array.DefsMain", "TestNested_Array_DefsMain",
+            mainDef, "test.nested.array", registry, options);
+
+        var result = sb.ToString();
+
+        // Assert: the transform property should wrap the inner List<string> in a
+        // CborListTypeInfo, not pass a StringCborConverter directly as the element
+        // converter for List<List<string>>.
+        // Correct: CborListTypeInfo<List<string>>( CborListTypeInfo<string>( StringCborConverter ) )
+        // Wrong:   CborListTypeInfo<List<string>>( StringCborConverter )
+        Assert.Contains("new CarpaNet.Cbor.CborListTypeInfo<global::System.Collections.Generic.List<string>>(new CarpaNet.Cbor.CborListTypeInfo<string>(new CarpaNet.Cbor.Converters.StringCborConverter()))", result);
+    }
+}