Validate Json schema using JsonSchema.NET

src/Microsoft.OpenApi.Hidi/Formatters/PowerShellFormatter.cs

@@ -348,9 +348,9 @@ private static JsonSchema CopySchema(JsonSchema schema, JsonSchema newSchema)
             {
                 schemaBuilder.MinProperties(minProperties);
             }
-            if (schema.GetDiscriminator() == null && newSchema.GetOpenApiDiscriminator() is { } discriminator)
+            if (schema.GetDiscriminator() == null && newSchema.GetDiscriminator() is { } discriminator)
             {
-                schemaBuilder.Discriminator(discriminator);
+                schemaBuilder.Discriminator(discriminator.PropertyName, discriminator.Mapping, discriminator.Extensions);
             }
             if (schema.GetOpenApiExternalDocs() == null && newSchema.GetOpenApiExternalDocs() is { } externalDocs)
             {

src/Microsoft.OpenApi/Extensions/JsonSchemaBuilderExtensions.cs

@@ -206,6 +206,7 @@ public void Evaluate(EvaluationContext context)
     /// The nullable keyword
     /// </summary>
     [SchemaKeyword(Name)]
+    [SchemaSpecVersion(SpecVersion.Draft202012)]
     public class NullableKeyword : IJsonSchemaKeyword
     {
         /// <summary>

src/Microsoft.OpenApi/Extensions/OpenApiElementExtensions.cs

@@ -24,6 +24,12 @@ public static class OpenApiElementExtensions
         public static IEnumerable<OpenApiError> Validate(this IOpenApiElement element, ValidationRuleSet ruleSet)
         {
             var validator = new OpenApiValidator(ruleSet);
+
+            if (element is OpenApiDocument doc)
+            {
+                validator.HostDocument = doc;
+            }
+
             var walker = new OpenApiWalker(validator);
             walker.Walk(element);
             return validator.Errors.Cast<OpenApiError>().Union(validator.Warnings);

src/Microsoft.OpenApi/Extensions/OpenApiTypeMapper.cs

@@ -130,6 +130,12 @@ public static Type MapJsonSchemaValueTypeToSimpleType(this JsonSchema schema)
             return result;
         }
 
+        /// <summary>
+        /// Converts the Schema value type to its string equivalent
+        /// </summary>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        /// <exception cref="NotSupportedException"></exception>
         internal static string ConvertSchemaValueTypeToString(SchemaValueType value)
         {
             return value switch

src/Microsoft.OpenApi/Models/OpenApiDocument.cs

@@ -128,7 +128,7 @@
 
             writer.WriteStartObject();
 
             // openApi;
             writer.WriteProperty(OpenApiConstants.OpenApi, "3.1.0");
 
             // jsonSchemaDialect
@@ -490,7 +490,7 @@
 
             if (poundIndex > 0)
             {
                 // External reference, ex: ./TodoReference.yaml#/components/schemas/todo
                 string externalUri = referenceUri.OriginalString.Split(pound).First();
                 Uri externalDocId = Workspace.GetDocumentId(externalUri);
                 string relativePath = referenceUri.OriginalString.Split(pound).Last();
@@ -676,7 +676,8 @@
         /// <exception cref="NotImplementedException"></exception>
         public JsonSchema FindSubschema(Json.Pointer.JsonPointer pointer, EvaluationOptions options)
         {
-            throw new NotImplementedException();
+            var locationUri = string.Concat(BaseUri, pointer);
+            return (JsonSchema)Workspace.ResolveReference<IBaseDocument>(locationUri);
         }
     }
 

src/Microsoft.OpenApi/Reader/ParseNodes/FixedFieldMap.cs

@@ -3,10 +3,11 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.OpenApi.Models;
 
 namespace Microsoft.OpenApi.Reader.ParseNodes
 {
-    internal class FixedFieldMap<T> : Dictionary<string, Action<T, ParseNode>>
+    internal class FixedFieldMap<T> : Dictionary<string, Action<T, ParseNode, OpenApiDocument>>
     {
     }
 }

src/Microsoft.OpenApi/Reader/ParseNodes/ListNode.cs

@@ -22,14 +22,14 @@ public ListNode(ParsingContext context, JsonArray jsonArray) : base(
             _nodeList = jsonArray;
         }
 
-        public override List<T> CreateList<T>(Func<MapNode, OpenApiDocument, T> map)
+        public override List<T> CreateList<T>(Func<MapNode, OpenApiDocument, T> map, OpenApiDocument hostDocument = null)
         {
             if (_nodeList == null)
             {
                 throw new OpenApiReaderException($"Expected list while parsing {typeof(T).Name}", _nodeList);
             }
 
-            return _nodeList?.Select(n => map(new MapNode(Context, n as JsonObject), null))
+            return _nodeList?.Select(n => map(new MapNode(Context, n as JsonObject), hostDocument))
                 .Where(i => i != null)
                 .ToList();
         }

src/Microsoft.OpenApi/Reader/ParseNodes/MapNode.cs

@@ -49,7 +49,7 @@ public PropertyNode this[string key]
             }
         }
 
-        public override Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument, T> map)
+        public override Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument, T> map, OpenApiDocument hostDocument = null)
         {
             var jsonMap = _node ?? throw new OpenApiReaderException($"Expected map while parsing {typeof(T).Name}", Context);
             var nodes = jsonMap.Select(
@@ -62,7 +62,7 @@ public override Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument
                     {
                         Context.StartObject(key);
                         value = n.Value is JsonObject jsonObject
-                          ? map(new MapNode(Context, jsonObject), null)
+                          ? map(new MapNode(Context, jsonObject), hostDocument)
                           : default;
                     }
                     finally
@@ -79,10 +79,11 @@ public override Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument
             return nodes.ToDictionary(k => k.key, v => v.value);
         }
 
-        public override Dictionary<string, JsonSchema> CreateJsonSchemaMapWithReference(
+        public override Dictionary<string, JsonSchema> CreateJsonSchemaMap(
             ReferenceType referenceType,
             Func<MapNode, OpenApiDocument, JsonSchema> map,
-            OpenApiSpecVersion version)
+            OpenApiSpecVersion version,
+            OpenApiDocument hostDocument = null)
         {
             var jsonMap = _node ?? throw new OpenApiReaderException($"Expected map while parsing {typeof(JsonSchema).Name}", Context);
 
@@ -95,30 +96,12 @@ public override Dictionary<string, JsonSchema> CreateJsonSchemaMapWithReference(
                     {
                         Context.StartObject(key);
                         entry = (key,
-                            value: map(new MapNode(Context, (JsonObject)n.Value), null)
+                            value: map(new MapNode(Context, (JsonObject)n.Value), hostDocument)
                         );
                         if (entry.value == null)
                         {
                             return default;  // Body Parameters shouldn't be converted to Parameters
                         }
-                        // If the component isn't a reference to another component, then point it to itself.
-                        if (entry.value.GetRef() == null)
-                        {
-                            var builder = new JsonSchemaBuilder();
-
-                            // construct the Ref and append it to the builder
-                            var reference = version == OpenApiSpecVersion.OpenApi2_0 ? string.Concat("#/definitions/", entry.key) :
-                                string.Concat("#/components/schemas/", entry.key);
-
-                            builder.Ref(reference);
-
-                            // Append all the keywords in original schema to our new schema using a builder instance
-                            foreach (var keyword in entry.value.Keywords)
-                            {
-                                builder.Add(keyword);
-                            }
-                            entry.value = builder.Build();
-                        }
                     }
                     finally
                     {

src/Microsoft.OpenApi/Reader/ParseNodes/ParseNode.cs

@@ -49,20 +49,21 @@ public static ParseNode Create(ParsingContext context, JsonNode node)
             return new ValueNode(context, node as JsonValue);
         }
 
-        public virtual List<T> CreateList<T>(Func<MapNode, OpenApiDocument, T> map)
+        public virtual List<T> CreateList<T>(Func<MapNode, OpenApiDocument, T> map, OpenApiDocument hostDocument = null)
         {
             throw new OpenApiReaderException("Cannot create list from this type of node.", Context);
         }
 
-        public virtual Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument, T> map)
+        public virtual Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument, T> map, OpenApiDocument hostDocument = null)
         {
             throw new OpenApiReaderException("Cannot create map from this type of node.", Context);
         }
 
-        public virtual Dictionary<string, JsonSchema> CreateJsonSchemaMapWithReference(
+        public virtual Dictionary<string, JsonSchema> CreateJsonSchemaMap(
             ReferenceType referenceType,
             Func<MapNode, OpenApiDocument, JsonSchema> map,
-            OpenApiSpecVersion version)
+            OpenApiSpecVersion version,
+            OpenApiDocument hostDocument = null)
         {
             throw new OpenApiReaderException("Cannot create map from this reference.", Context);
         }

src/Microsoft.OpenApi/Reader/ParseNodes/PatternFieldMap.cs

@@ -3,10 +3,11 @@
 
 using System;
 using System.Collections.Generic;
+using Microsoft.OpenApi.Models;
 
 namespace Microsoft.OpenApi.Reader.ParseNodes
 {
-    internal class PatternFieldMap<T> : Dictionary<Func<string, bool>, Action<T, string, ParseNode>>
+    internal class PatternFieldMap<T> : Dictionary<Func<string, bool>, Action<T, string, ParseNode, OpenApiDocument>>
     {
     }
 }

src/Microsoft.OpenApi/Reader/ParseNodes/PropertyNode.cs

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
@@ -26,15 +26,16 @@ public PropertyNode(ParsingContext context, string name, JsonNode node) : base(
 
         public void ParseField<T>(
             T parentInstance,
-            IDictionary<string, Action<T, ParseNode>> fixedFields,
-            IDictionary<Func<string, bool>, Action<T, string, ParseNode>> patternFields)
+            IDictionary<string, Action<T, ParseNode, OpenApiDocument>> fixedFields,
+            IDictionary<Func<string, bool>, Action<T, string, ParseNode, OpenApiDocument>> patternFields,
+            OpenApiDocument hostDocument = null)
         {
             if (fixedFields.TryGetValue(Name, out var fixedFieldMap))
             {
                 try
                 {
                     Context.StartObject(Name);
-                    fixedFieldMap(parentInstance, Value);
+                    fixedFieldMap(parentInstance, Value, hostDocument);
                 }
                 catch (OpenApiReaderException ex)
                 {
@@ -58,7 +59,7 @@ public void ParseField<T>(
                     try
                     {
                         Context.StartObject(Name);
-                        map(parentInstance, Name, Value);
+                        map(parentInstance, Name, Value, hostDocument);
                     }
                     catch (OpenApiReaderException ex)
                     {