Inline dictionary or array inheritance (#785)

* Inline dictionary or array inheritance

* Fix c# generation

src/NJsonSchema.CodeGeneration.CSharp.Tests/EnumTests.cs

@@ -226,5 +226,38 @@ public async Task When_type_name_hint_has_generics_then_they_are_converted()
             /// Assert
             Assert.Contains("public enum FirstMetdodOfMetValueGroupChar", code);
         }
+
+        [Fact]
+        public async Task When_enum_property_is_not_required_in_Swagger2_then_it_is_nullable()
+        {
+            //// Arrange
+            var json =
+            @"{
+    ""type"": ""object"",
+    ""required"": [
+        ""name"",
+        ""photoUrls""
+    ],
+    ""properties"": {
+        ""status"": {
+            ""type"": ""string"",
+            ""description"": ""pet status in the store"",
+            ""enum"": [
+                ""available"",
+                ""pending"",
+                ""sold""
+            ]
+        }
+    }
+}";
+            var schema = await JsonSchema4.FromJsonAsync(json);
+            var generator = new CSharpGenerator(schema, new CSharpGeneratorSettings { SchemaType = SchemaType.Swagger2 });
+
+            //// Act
+            var code = generator.GenerateFile("MyClass");
+
+            //// Assert
+            Assert.Contains("private MyClassStatus? _status;", code);
+        }
     }
 }

src/NJsonSchema.CodeGeneration.CSharp.Tests/InheritanceTests.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using NJsonSchema.CodeGeneration.CSharp;
+using Xunit;
+
+namespace NJsonSchema.CodeGeneration.Tests.CSharp
+{
+    public class InheritanceTests
+    {
+        public class MyContainer
+        {
+            public EmptyClassInheritingDictionary CustomDictionary { get; set; }
+        }
+
+        public sealed class EmptyClassInheritingDictionary : Dictionary<string, object>
+        {
+        }
+
+        [Fact]
+        public async Task When_empty_class_inherits_from_dictionary_then_allOf_inheritance_still_works()
+        {
+            //// Arrange
+            var schema = await JsonSchema4.FromTypeAsync<MyContainer>();
+            var data = schema.ToJson();
+
+            var generator = new CSharpGenerator(schema, new CSharpGeneratorSettings());
+
+            //// Act
+            var code = generator.GenerateFile();
+
+            //// Assert
+            var dschema = schema.Definitions["EmptyClassInheritingDictionary"];
+            Assert.Equal(0, dschema.AllOf.Count);
+            Assert.True(dschema.IsDictionary);
+
+            Assert.Contains("public EmptyClassInheritingDictionary CustomDictionary", code);
+            Assert.Contains("public partial class EmptyClassInheritingDictionary : System.Collections.Generic.Dictionary<string, object>", code);
+        }
+    }
+}

src/NJsonSchema.CodeGeneration.CSharp/CSharpTypeResolver.cs

@@ -42,6 +42,17 @@ public CSharpTypeResolver(CSharpGeneratorSettings settings, JsonSchema4 exceptio
         /// <param name="typeNameHint">The type name hint to use when generating the type and the type name is missing.</param>
         /// <returns>The type name.</returns>
         public override string Resolve(JsonSchema4 schema, bool isNullable, string typeNameHint)
+        {
+            return Resolve(schema, isNullable, typeNameHint, true);
+        }
+
+        /// <summary>Resolves and possibly generates the specified schema.</summary>
+        /// <param name="schema">The schema.</param>
+        /// <param name="isNullable">Specifies whether the given type usage is nullable.</param>
+        /// <param name="typeNameHint">The type name hint to use when generating the type and the type name is missing.</param>
+        /// <param name="checkForExistingSchema">Checks whether a named schema is already registered.</param>
+        /// <returns>The type name.</returns>
+        public string Resolve(JsonSchema4 schema, bool isNullable, string typeNameHint, bool checkForExistingSchema)
         {
             schema = schema.ActualSchema;
 
@@ -59,9 +70,6 @@ public override string Resolve(JsonSchema4 schema, bool isNullable, string typeN
                     JsonObjectType.String;
             }
 
-            if (type.HasFlag(JsonObjectType.Array))
-                return ResolveArrayOrTuple(schema);
-
             if (type.HasFlag(JsonObjectType.Number))
                 return ResolveNumber(schema, isNullable);
 
@@ -74,6 +82,12 @@ public override string Resolve(JsonSchema4 schema, bool isNullable, string typeN
             if (type.HasFlag(JsonObjectType.String))
                 return ResolveString(schema, isNullable, typeNameHint);
 
+            if (Types.ContainsKey(schema) && checkForExistingSchema)
+                return Types[schema];
+
+            if (type.HasFlag(JsonObjectType.Array))
+                return ResolveArrayOrTuple(schema);
+
             if (type.HasFlag(JsonObjectType.File))
                 return "byte[]";
 
@@ -83,6 +97,19 @@ public override string Resolve(JsonSchema4 schema, bool isNullable, string typeN
             return GetOrGenerateTypeName(schema, typeNameHint);
         }
 
+        /// <summary>Checks whether the given schema should generate a type.</summary>
+        /// <param name="schema">The schema.</param>
+        /// <returns>True if the schema should generate a type.</returns>
+        protected override bool IsTypeSchema(JsonSchema4 schema)
+        {
+            if (schema.IsDictionary || schema.IsArray)
+            {
+                return true;
+            }
+
+            return base.IsTypeSchema(schema);
+        }
+
         private string ResolveString(JsonSchema4 schema, bool isNullable, string typeNameHint)
         {
             if (schema.Format == JsonFormatStrings.Date)

src/NJsonSchema.CodeGeneration.CSharp/Models/ClassTemplateModel.cs

@@ -39,7 +39,7 @@ public class ClassTemplateModel : ClassTemplateModelBase
                 .Select(property => new PropertyModel(this, property, _resolver, _settings))
                 .ToArray();
 
-            if (HasInheritance)
+            if (schema.InheritedSchema != null)
             {
                 BaseClass = new ClassTemplateModel(BaseClassName, settings, resolver, schema.InheritedSchema, rootObject);
                 AllProperties = Properties.Concat(BaseClass.AllProperties).ToArray();
@@ -95,10 +95,10 @@ public class ClassTemplateModel : ClassTemplateModelBase
         public string Discriminator => _schema.Discriminator;
 
         /// <summary>Gets a value indicating whether the class has a parent class.</summary>
-        public bool HasInheritance => _schema.InheritedSchema != null;
+        public bool HasInheritance => _schema.InheritedTypeSchema != null;
 
         /// <summary>Gets the base class name.</summary>
-        public string BaseClassName => HasInheritance ? _resolver.Resolve(_schema.InheritedSchema, false, string.Empty)
+        public string BaseClassName => HasInheritance ? _resolver.Resolve(_schema.InheritedTypeSchema, false, string.Empty, false)
                 .Replace(_settings.ArrayType + "<", _settings.ArrayBaseType + "<")
                 .Replace(_settings.DictionaryType + "<", _settings.DictionaryBaseType + "<") : null;
 

src/NJsonSchema.CodeGeneration.TypeScript.Tests/InheritanceTests.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace NJsonSchema.CodeGeneration.TypeScript.Tests
+{
+    public class InheritanceTests
+    {
+        public class MyContainer
+        {
+            public EmptyClassInheritingDictionary CustomDictionary { get; set; }
+        }
+
+        public sealed class EmptyClassInheritingDictionary : Dictionary<string, object>
+        {
+        }
+
+        [Fact]
+        public async Task When_empty_class_inherits_from_dictionary_then_allOf_inheritance_still_works()
+        {
+            //// Arrange
+            var schema = await JsonSchema4.FromTypeAsync<MyContainer>();
+            var data = schema.ToJson();
+
+            var generator = new TypeScriptGenerator(schema, new TypeScriptGeneratorSettings { TypeScriptVersion = 2.0m });
+
+            //// Act
+            var code = generator.GenerateFile("ContainerClass");
+
+            //// Assert
+            var dschema = schema.Definitions["EmptyClassInheritingDictionary"];
+            Assert.Equal(0, dschema.AllOf.Count);
+            Assert.True(dschema.IsDictionary);
+
+            Assert.DoesNotContain("EmptyClassInheritingDictionary", code);
+            Assert.Contains("customDictionary: { [key: string] : any; } | undefined;", code);
+        }
+    }
+}

src/NJsonSchema.CodeGeneration/CodeArtifact.cs

@@ -6,6 +6,8 @@
 // <author>Rico Suter, mail@rsuter.com</author>
 //-----------------------------------------------------------------------
 
+using System;
+
 namespace NJsonSchema.CodeGeneration
 {
     /// <summary>The type generator result.</summary>
@@ -49,6 +51,11 @@ public CodeArtifact(string typeName, CodeArtifactType type, CodeArtifactLanguage
         /// <param name="template">The template to render the code.</param>
         public CodeArtifact(string typeName, string baseTypeName, CodeArtifactType type, CodeArtifactLanguage language, ITemplate template)
         {
+            if (typeName == baseTypeName)
+            {
+                throw new ArgumentException("The baseTypeName cannot equal typeName.", nameof(typeName));
+            }
+
             TypeName = typeName;
             BaseTypeName = baseTypeName;
 

src/NJsonSchema.CodeGeneration/TypeResolverBase.cs

@@ -70,15 +70,27 @@ public void RegisterSchemaDefinitions(IDictionary<string, JsonSchema4> definitio
                 foreach (var pair in definitions)
                 {
                     var schema = pair.Value.ActualSchema;
-                    var isCodeGeneratingSchema = !schema.IsDictionary && !schema.IsAnyType &&
-                        (schema.IsEnumeration || schema.Type == JsonObjectType.None || schema.Type.HasFlag(JsonObjectType.Object));
 
-                    if (isCodeGeneratingSchema)
+                    if (IsTypeSchema(schema))
+                    {
                         GetOrGenerateTypeName(schema, pair.Key);
+                    }
                 }
             }
         }
 
+        /// <summary>Checks whether the given schema should generate a type.</summary>
+        /// <param name="schema">The schema.</param>
+        /// <returns>True if the schema should generate a type.</returns>
+        protected virtual bool IsTypeSchema(JsonSchema4 schema)
+        {
+            return !schema.IsDictionary &&
+                   !schema.IsAnyType &&
+                   (schema.IsEnumeration ||
+                    schema.Type == JsonObjectType.None ||
+                    schema.Type.HasFlag(JsonObjectType.Object));
+        }
+
         /// <summary>Resolves the type of the dictionary value of the given schema (must be a dictionary schema).</summary>
         /// <param name="schema">The schema.</param>
         /// <param name="fallbackType">The fallback type (e.g. 'object').</param>

src/NJsonSchema/Generation/JsonSchemaGenerator.cs

@@ -700,26 +700,46 @@ private async Task<JsonSchema4> GenerateInheritanceAsync(Type type, JsonSchema4
                     else
                     {
                         var actualSchema = new JsonSchema4();
+
                         await GeneratePropertiesAsync(type, actualSchema, schemaResolver).ConfigureAwait(false);
                         await ApplyAdditionalPropertiesAsync(type, actualSchema, schemaResolver).ConfigureAwait(false);
 
-                        var baseSchema = await GenerateAsync(baseType, schemaResolver).ConfigureAwait(false);
                         var baseTypeInfo = Settings.ReflectionService.GetDescription(baseType, null, Settings);
-                        if (baseTypeInfo.RequiresSchemaReference(Settings.TypeMappers))
+                        var requiresSchemaReference = baseTypeInfo.RequiresSchemaReference(Settings.TypeMappers);
+
+                        if (actualSchema.Properties.Any() || requiresSchemaReference)
                         {
-                            if (schemaResolver.RootObject != baseSchema.ActualSchema)
-                                schemaResolver.AppendSchema(baseSchema.ActualSchema, Settings.SchemaNameGenerator.Generate(baseType));
+                            // Use allOf inheritance only if the schema is an object with properties 
+                            // (not empty class which just inherits from array or dictionary)
 
-                            schema.AllOf.Add(new JsonSchema4
+                            var baseSchema = await GenerateAsync(baseType, schemaResolver).ConfigureAwait(false);
+                            if (requiresSchemaReference)
+                            {
+                                if (schemaResolver.RootObject != baseSchema.ActualSchema)
+                                {
+                                    schemaResolver.AppendSchema(baseSchema.ActualSchema, Settings.SchemaNameGenerator.Generate(baseType));
+                                }
+
+                                schema.AllOf.Add(new JsonSchema4
+                                {
+                                    Reference = baseSchema.ActualSchema
+                                });
+                            }
+                            else
                             {
-                                Reference = baseSchema.ActualSchema
-                            });
+                                schema.AllOf.Add(baseSchema);
+                            }
+
+                            // First schema is the (referenced) base schema, second is the type schema itself
+                            schema.AllOf.Add(actualSchema);
+                            return actualSchema;
                         }
                         else
-                            schema.AllOf.Add(baseSchema);
-
-                        schema.AllOf.Add(actualSchema);
-                        return actualSchema;
+                        {
+                            // Array and dictionary inheritance are not expressed with allOf but inline
+                            await GenerateAsync(baseType, null, schema, schemaResolver).ConfigureAwait(false);
+                            return schema;
+                        }
                     }
                 }
             }

src/NJsonSchema/JsonSchema4.cs

@@ -205,11 +205,7 @@ internal static JsonSchema4 FromJsonWithoutReferenceHandling(string data)
         /// <summary>Gets the inherited/parent schema (most probable base schema in allOf).</summary>
         /// <remarks>Used for code generation.</remarks>
         [JsonIgnore]
-#if !LEGACY
-        public JsonSchema4 InheritedSchema
-#else
         public JsonSchema4 InheritedSchema
-#endif
         {
             get
             {
@@ -229,6 +225,21 @@ public JsonSchema4 InheritedSchema
             }
         }
 
+        /// <summary>Gets the inherited/parent schema which may also be inlined 
+        /// (the schema itself if it is a dictionary or array, otherwise <see cref="InheritedSchema"/>).</summary>
+        /// <remarks>Used for code generation.</remarks>
+        [JsonIgnore]
+        public JsonSchema4 InheritedTypeSchema
+        {
+            get
+            {
+                if (ActualTypeSchema.IsDictionary || ActualTypeSchema.IsArray)
+                    return ActualTypeSchema;
+
+                return InheritedSchema;
+            }
+        }
+
         /// <summary>Gets the list of all inherited/parent schemas.</summary>
         /// <remarks>Used for code generation.</remarks>
         [JsonIgnore]