fix: implementation drift between the different version services

src/Microsoft.OpenApi/Reader/BaseOpenApiVersionService.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Microsoft.OpenApi.Reader;
+
+internal abstract class BaseOpenApiVersionService : IOpenApiVersionService
+{
+    public OpenApiDiagnostic Diagnostic { get; }
+
+    protected BaseOpenApiVersionService(OpenApiDiagnostic diagnostic)
+    {
+        Diagnostic = diagnostic;
+    }
+
+    internal abstract Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> Loaders { get; }
+
+    public abstract OpenApiDocument LoadDocument(RootNode rootNode, Uri location);
+
+    public T? LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
+    {
+        if (Loaders.TryGetValue(typeof(T), out var loader) && loader(node, doc) is T result)
+        {
+            return result;
+        }
+        return default;
+    }
+    public virtual string? GetReferenceScalarValues(MapNode mapNode, string scalarValue)
+    {
+        if (mapNode.Any(static x => !"$ref".Equals(x.Name, StringComparison.OrdinalIgnoreCase)) &&
+            mapNode
+            .Where(x => x.Name.Equals(scalarValue))
+            .Select(static x => x.Value)
+            .OfType<ValueNode>().FirstOrDefault() is {} valueNode)
+        {
+            return valueNode.GetScalarValue();
+        }
+
+        return null;
+    } 
+}

src/Microsoft.OpenApi/Reader/V2/OpenApiV2VersionService.cs

@@ -10,17 +10,14 @@ namespace Microsoft.OpenApi.Reader.V2
     /// <summary>
     /// The version specific implementations for OpenAPI V2.0.
     /// </summary>
-    internal class OpenApiV2VersionService : IOpenApiVersionService
+    internal class OpenApiV2VersionService : BaseOpenApiVersionService
     {
-        public OpenApiDiagnostic Diagnostic { get; }
-
         /// <summary>
         /// Create Parsing Context
         /// </summary>
         /// <param name="diagnostic">Provide instance for diagnostic object for collecting and accessing information about the parsing.</param>
-        public OpenApiV2VersionService(OpenApiDiagnostic diagnostic)
+        public OpenApiV2VersionService(OpenApiDiagnostic diagnostic): base(diagnostic)
         {
-            Diagnostic = diagnostic;
         }
 
         private readonly Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> _loaders = new()
@@ -44,22 +41,13 @@ public OpenApiV2VersionService(OpenApiDiagnostic diagnostic)
             [typeof(OpenApiXml)] = OpenApiV2Deserializer.LoadXml
         };
 
-        public OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
+        public override OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
         {
             return OpenApiV2Deserializer.LoadOpenApi(rootNode, location);
         }
+        internal override Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> Loaders => _loaders;
 
-        public T? LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
-        {
-            if (_loaders.TryGetValue(typeof(T), out var loader) && loader(node, doc) is T result)
-            {
-                return result;
-            }
-            return default;
-        }
-
-        /// <inheritdoc />
-        public string GetReferenceScalarValues(MapNode mapNode, string scalarValue)
+        public override string GetReferenceScalarValues(MapNode mapNode, string scalarValue)
         {
             throw new InvalidOperationException();
         }

src/Microsoft.OpenApi/Reader/V3/OpenApiV3VersionService.cs

@@ -3,29 +3,24 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 
 namespace Microsoft.OpenApi.Reader.V3
 {
     /// <summary>
     /// The version service for the Open API V3.0.
     /// </summary>
-    internal class OpenApiV3VersionService : IOpenApiVersionService
+    internal class OpenApiV3VersionService : BaseOpenApiVersionService
     {
-        public OpenApiDiagnostic Diagnostic { get; }
-
-        private static readonly char[] _pathSeparator = new char[] { '/' };
 
         /// <summary>
         /// Create Parsing Context
         /// </summary>
         /// <param name="diagnostic">Provide instance for diagnostic object for collecting and accessing information about the parsing.</param>
-        public OpenApiV3VersionService(OpenApiDiagnostic diagnostic)
+        public OpenApiV3VersionService(OpenApiDiagnostic diagnostic):base(diagnostic)
         {
-            Diagnostic = diagnostic;
         }
 
-        private readonly Dictionary<Type, Func<ParseNode, OpenApiDocument, object>> _loaders = new()
+        private readonly Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> _loaders = new()
         {
             [typeof(JsonNodeExtension)] = OpenApiV3Deserializer.LoadAny,
             [typeof(OpenApiCallback)] = OpenApiV3Deserializer.LoadCallback,
@@ -59,29 +54,11 @@ public OpenApiV3VersionService(OpenApiDiagnostic diagnostic)
             [typeof(OpenApiSchemaReference)] = OpenApiV3Deserializer.LoadMapping
         };
 
-        public OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
-        {
-            return OpenApiV3Deserializer.LoadOpenApi(rootNode, location);
-        }
+        internal override Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> Loaders => _loaders;
 
-        public T LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
+        public override OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
         {
-            return (T)_loaders[typeof(T)](node, doc);
+            return OpenApiV3Deserializer.LoadOpenApi(rootNode, location);
         }
-
-        /// <inheritdoc />
-        public string? GetReferenceScalarValues(MapNode mapNode, string scalarValue)
-        {
-            if (mapNode.Any(static x => !"$ref".Equals(x.Name, StringComparison.OrdinalIgnoreCase)) &&
-                mapNode
-                .Where(x => x.Name.Equals(scalarValue))
-                .Select(static x => x.Value)
-                .OfType<ValueNode>().FirstOrDefault() is {} valueNode)
-            {
-                return valueNode.GetScalarValue();
-            }
-
-            return null;
-        }        
     }
 }

src/Microsoft.OpenApi/Reader/V31/OpenApiV31VersionService.cs

@@ -3,34 +3,30 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using Microsoft.OpenApi.Reader.V3;
 
 namespace Microsoft.OpenApi.Reader.V31
 {
     /// <summary>
     /// The version service for the Open API V3.1.
     /// </summary>
-    internal class OpenApiV31VersionService : IOpenApiVersionService
+    internal class OpenApiV31VersionService : BaseOpenApiVersionService
     {
-        public OpenApiDiagnostic Diagnostic { get; }
 
         /// <summary>
         /// Create Parsing Context
         /// </summary>
         /// <param name="diagnostic">Provide instance for diagnotic object for collecting and accessing information about the parsing.</param>
-        public OpenApiV31VersionService(OpenApiDiagnostic diagnostic)
+        public OpenApiV31VersionService(OpenApiDiagnostic diagnostic):base(diagnostic)
         {
-            Diagnostic = diagnostic;
         }
 
-        private readonly Dictionary<Type, Func<ParseNode, OpenApiDocument, object>> _loaders = new Dictionary<Type, Func<ParseNode, OpenApiDocument, object>>
+        private readonly Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> _loaders = new Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>>
         {
             [typeof(JsonNodeExtension)] = OpenApiV31Deserializer.LoadAny,
             [typeof(OpenApiCallback)] = OpenApiV31Deserializer.LoadCallback,
             [typeof(OpenApiComponents)] = OpenApiV31Deserializer.LoadComponents,
             [typeof(OpenApiContact)] = OpenApiV31Deserializer.LoadContact,
-            [typeof(OpenApiDiscriminator)] = OpenApiV3Deserializer.LoadDiscriminator,
+            [typeof(OpenApiDiscriminator)] = OpenApiV31Deserializer.LoadDiscriminator,
             [typeof(OpenApiEncoding)] = OpenApiV31Deserializer.LoadEncoding,
             [typeof(OpenApiExample)] = OpenApiV31Deserializer.LoadExample,
             [typeof(OpenApiExternalDocs)] = OpenApiV31Deserializer.LoadExternalDocs,
@@ -58,28 +54,11 @@ public OpenApiV31VersionService(OpenApiDiagnostic diagnostic)
             [typeof(OpenApiSchemaReference)] = OpenApiV31Deserializer.LoadMapping
         };
 
-        public OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
+        public override OpenApiDocument LoadDocument(RootNode rootNode, Uri location)
         {
             return OpenApiV31Deserializer.LoadOpenApi(rootNode, location);
         }
+        internal override Dictionary<Type, Func<ParseNode, OpenApiDocument, object?>> Loaders => _loaders;
 
-        public T LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
-        {
-            return (T)_loaders[typeof(T)](node, doc);
-        }
-
-        /// <inheritdoc />
-        public string? GetReferenceScalarValues(MapNode mapNode, string scalarValue)
-        {
-            if (mapNode.Any(static x => !"$ref".Equals(x.Name, StringComparison.OrdinalIgnoreCase)))
-            {
-                var valueNode = mapNode.Where(x => x.Name.Equals(scalarValue))
-                .Select(static x => x.Value).OfType<ValueNode>().FirstOrDefault();
-
-                return valueNode?.GetScalarValue();
-            }
-
-            return null;
-        }
     }
 }