Handling of nested arrays

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Aligns naming of sliced OpenAPI description generated by `plugin add` should be named `<plugin-name>-openapi.json|yml`
 - Fixed RPC server to respect the `KIOTA_CONFIG_PREVIEW` flag.
+- Fixed handling of nested arrays to be handled as `UntypedNode` instances [#4549](https://github.com/microsoft/kiota/issues/4549)
 
 ## [1.14.0] - 2024-05-02
 

src/Kiota.Builder/KiotaBuilder.cs

@@ -1012,7 +1012,7 @@
 
         if (!"string".Equals(parameter.Type.Name, StringComparison.OrdinalIgnoreCase) && config.IncludeBackwardCompatible)
         { // adding a second indexer for the string version of the parameter so we keep backward compatibility
             //TODO remove for v2
             var backCompatibleValue = (CodeIndexer)result[0].Clone();
             backCompatibleValue.Name += "-string";
             backCompatibleValue.IndexParameter.Type = DefaultIndexerParameterType;
@@ -1166,7 +1166,7 @@
             var suffix = $"{operationType}Response";
             var modelType = CreateModelDeclarations(currentNode, schema, operation, parentClass, suffix);
             if (modelType is not null && config.IncludeBackwardCompatible && config.Language is GenerationLanguage.CSharp or GenerationLanguage.Go && modelType.Name.EndsWith(suffix, StringComparison.Ordinal))
             { //TODO remove for v2
                 var obsoleteTypeName = modelType.Name[..^suffix.Length] + "Response";
                 if (modelType is CodeType codeType &&
                     codeType.TypeDefinition is CodeClass codeClass)
@@ -1299,7 +1299,7 @@
             executorMethod.AddParameter(cancellationParam);// Add cancellation token parameter
 
             if (returnTypes.Item2 is not null && config.IncludeBackwardCompatible)
             { //TODO remove for v2
                 var additionalExecutorMethod = (CodeMethod)executorMethod.Clone();
                 additionalExecutorMethod.ReturnType = returnTypes.Item2;
                 additionalExecutorMethod.OriginalMethod = executorMethod;
@@ -1693,7 +1693,8 @@
             return CreateModelDeclarationAndType(currentNode, schema, operation, codeNamespace, suffix, response: responseValue, typeNameForInlineSchema: typeNameForInlineSchema, isRequestBody);
         }
 
-        if (schema.IsArray())
+        if (schema.IsArray() &&
+            !schema.Items.IsArray()) // Only handle collections of primitives and complex types. Otherwise, multi-dimensional arrays would be recursively unwrapped undesirably to lead to incorrect serialization types. 
         {
             // collections at root
             return CreateCollectionModelDeclaration(currentNode, schema, operation, codeNamespace, typeNameForInlineSchema, isRequestBody);
@@ -2308,7 +2309,7 @@
         if (!parameterClass.ContainsPropertyWithWireName(prop.WireName))
         {
             if (addBackwardCompatibleParameter && config.IncludeBackwardCompatible && config.Language is GenerationLanguage.CSharp or GenerationLanguage.Go)
             { //TODO remove for v2
                 var modernProp = (CodeProperty)prop.Clone();
                 modernProp.Name = $"{prop.Name}As{modernProp.Type.Name.ToFirstCharacterUpperCase()}";
                 modernProp.SerializationName = prop.WireName;

tests/Kiota.Builder.Tests/KiotaBuilderTests.cs

@@ -1273,6 +1273,74 @@ public void OData_doubles_as_any_of()
         Assert.Equal("double", progressProp.Type.Name);
     }
     [Fact]
+    public void MultiNestedArraysSupportedAsUntypedNodes()
+    {
+        var fooSchema = new OpenApiSchema
+        {
+            Type = "object",
+            Properties = new Dictionary<string, OpenApiSchema> {
+                {
+                    "sortBy", new OpenApiSchema {
+                        Type = "array",
+                        Items = new OpenApiSchema {
+                            Type = "array",
+                            Items = new OpenApiSchema {
+                                Type = "string"
+                            }
+                        }
+                    }
+                },
+            },
+            Reference = new OpenApiReference
+            {
+                Id = "#/components/schemas/bar.foo"
+            },
+            UnresolvedReference = false
+        };
+        var document = new OpenApiDocument
+        {
+            Paths = new OpenApiPaths
+            {
+                ["foos/{id}"] = new OpenApiPathItem
+                {
+                    Operations = {
+                        [OperationType.Get] = new OpenApiOperation
+                        {
+                            Responses = new OpenApiResponses {
+                                ["200"] = new OpenApiResponse
+                                {
+                                    Content = {
+                                        ["application/json"] = new OpenApiMediaType
+                                        {
+                                            Schema = fooSchema
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+            },
+            Components = new OpenApiComponents
+            {
+                Schemas = new Dictionary<string, OpenApiSchema> {
+                    {
+                        "bar.foo", fooSchema
+                    }
+                }
+            }
+        };
+        var mockLogger = new CountLogger<KiotaBuilder>();
+        var builder = new KiotaBuilder(mockLogger, new GenerationConfiguration { ClientClassName = "Graph", ApiRootUrl = "https://localhost" }, _httpClient);
+        var node = builder.CreateUriSpace(document);
+        var codeModel = builder.CreateSourceModel(node);
+        var fooClass = codeModel.FindNamespaceByName("ApiSdk.models").FindChildByName<CodeClass>("foo");
+        Assert.NotNull(fooClass);
+        var sortByProp = fooClass.FindChildByName<CodeProperty>("sortBy", false);
+        Assert.NotNull(sortByProp);
+        Assert.Equal(KiotaBuilder.UntypedNodeName, sortByProp.Type.Name);// nested array property an UntypedNode
+    }
+    [Fact]
     public void Object_Arrays_are_supported()
     {
         var userSchema = new OpenApiSchema