feat: Added Nullability markup for some classes

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

@@ -54,7 +54,8 @@ public override void Visit(ref JsonSchema schema)
 
         public override void Visit(OpenApiPathItem pathItem)
         {
-            if (pathItem.Operations.TryGetValue(OperationType.Put, out var value))
+            if (pathItem.Operations.TryGetValue(OperationType.Put, out var value) &&
+                value.OperationId != null)
             {
                 var operationId = value.OperationId;
                 pathItem.Operations[OperationType.Put].OperationId = ResolvePutOperationId(operationId);
@@ -69,14 +70,14 @@ public override void Visit(OpenApiOperation operation)
                 throw new ArgumentException($"OperationId is required {PathString}", nameof(operation));
 
             var operationId = operation.OperationId;
-            var operationTypeExtension = operation.Extensions.GetExtension("x-ms-docs-operation-type");
+            var operationTypeExtension = operation.Extensions?.GetExtension("x-ms-docs-operation-type");
             if (operationTypeExtension.IsEquals("function"))
-                operation.Parameters = ResolveFunctionParameters(operation.Parameters);
+                operation.Parameters = ResolveFunctionParameters(operation.Parameters ?? new List<OpenApiParameter>());
 
             // Order matters. Resolve operationId.
             operationId = RemoveHashSuffix(operationId);
             if (operationTypeExtension.IsEquals("action") || operationTypeExtension.IsEquals("function"))
-                operationId = RemoveKeyTypeSegment(operationId, operation.Parameters);
+                operationId = RemoveKeyTypeSegment(operationId, operation.Parameters ?? new List<OpenApiParameter>());
             operationId = SingularizeAndDeduplicateOperationId(operationId.SplitByChar('.'));
             operationId = ResolveODataCastOperationId(operationId);
             operationId = ResolveByRefOperationId(operationId);

src/Microsoft.OpenApi.Hidi/OpenApiService.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;
@@ -185,7 +185,7 @@ private static OpenApiDocument ApplyFilters(HidiOptions options, ILogger logger,
                 stopwatch.Start();
                 document = OpenApiFilterService.CreateFilteredDocument(document, predicate);
                 stopwatch.Stop();
-                logger.LogTrace("{Timestamp}ms: Creating filtered OpenApi document with {Paths} paths.", stopwatch.ElapsedMilliseconds, document.Paths.Count);
+                logger.LogTrace("{Timestamp}ms: Creating filtered OpenApi document with {Paths} paths.", stopwatch.ElapsedMilliseconds, document.Paths?.Count);
             }
 
             return document;
@@ -248,7 +248,7 @@ private static async Task<OpenApiDocument> GetOpenApi(HidiOptions options, strin
 
                     document = await ConvertCsdlToOpenApi(filteredStream ?? stream, format, metadataVersion, options.SettingsConfig, cancellationToken).ConfigureAwait(false);
                     stopwatch.Stop();
-                    logger.LogTrace("{Timestamp}ms: Generated OpenAPI with {Paths} paths.", stopwatch.ElapsedMilliseconds, document.Paths.Count);
+                    logger.LogTrace("{Timestamp}ms: Generated OpenAPI with {Paths} paths.", stopwatch.ElapsedMilliseconds, document.Paths?.Count);
                 }
             }
             else if (!string.IsNullOrEmpty(options.OpenApi))
@@ -666,7 +666,7 @@ internal static void WriteTreeDocumentAsMarkdown(string openapiUrl, OpenApiDocum
         {
             var rootNode = OpenApiUrlTreeNode.Create(document, "main");
 
-            writer.WriteLine("# " + document.Info.Title);
+            writer.WriteLine("# " + document.Info?.Title);
             writer.WriteLine();
             writer.WriteLine("API Description: " + openapiUrl);
 
@@ -702,7 +702,7 @@ internal static void WriteTreeDocumentAsHtml(string sourceUrl, OpenApiDocument d
                 </style>
                 <body>
                 """);
-            writer.WriteLine("<h1>" + document.Info.Title + "</h1>");
+            writer.WriteLine("<h1>" + document.Info?.Title + "</h1>");
             writer.WriteLine();
             writer.WriteLine($"<h3> API Description: <a href='{sourceUrl}'>{sourceUrl}</a></h3>");
 
@@ -773,8 +773,8 @@ internal static async Task PluginManifest(HidiOptions options, ILogger logger, C
             // Create OpenAIPluginManifest from ApiDependency and OpenAPI document
             var manifest = new OpenAIPluginManifest
             {
-                NameForHuman = document.Info.Title,
-                DescriptionForHuman = document.Info.Description,
+                NameForHuman = document.Info?.Title,
+                DescriptionForHuman = document.Info?.Description,
                 Api = new()
                 {
                     Type = "openapi",

src/Microsoft.OpenApi/Models/OpenApiComponents.cs

@@ -8,6 +8,7 @@
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Writers;
 
+#nullable enable
 
 namespace Microsoft.OpenApi.Models
 {
@@ -19,60 +20,60 @@ public class OpenApiComponents : IOpenApiSerializable, IOpenApiExtensible
         /// <summary>
         /// An object to hold reusable <see cref="JsonSchema"/> Objects.
         /// </summary>
-        public IDictionary<string, JsonSchema> Schemas { get; set; } = new Dictionary<string, JsonSchema>();
+        public IDictionary<string, JsonSchema>? Schemas { get; set; } = new Dictionary<string, JsonSchema>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiResponse"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiResponse> Responses { get; set; } = new Dictionary<string, OpenApiResponse>();
+        public virtual IDictionary<string, OpenApiResponse>? Responses { get; set; } = new Dictionary<string, OpenApiResponse>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiParameter"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiParameter> Parameters { get; set; } =
+        public virtual IDictionary<string, OpenApiParameter>? Parameters { get; set; } =
             new Dictionary<string, OpenApiParameter>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiExample"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiExample> Examples { get; set; } = new Dictionary<string, OpenApiExample>();
+        public virtual IDictionary<string, OpenApiExample>? Examples { get; set; } = new Dictionary<string, OpenApiExample>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiRequestBody"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiRequestBody> RequestBodies { get; set; } =
+        public virtual IDictionary<string, OpenApiRequestBody>? RequestBodies { get; set; } =
             new Dictionary<string, OpenApiRequestBody>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiHeader"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiHeader> Headers { get; set; } = new Dictionary<string, OpenApiHeader>();
+        public virtual IDictionary<string, OpenApiHeader>? Headers { get; set; } = new Dictionary<string, OpenApiHeader>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiSecurityScheme"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiSecurityScheme> SecuritySchemes { get; set; } =
+        public virtual IDictionary<string, OpenApiSecurityScheme>? SecuritySchemes { get; set; } =
             new Dictionary<string, OpenApiSecurityScheme>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiLink"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiLink> Links { get; set; } = new Dictionary<string, OpenApiLink>();
+        public virtual IDictionary<string, OpenApiLink>? Links { get; set; } = new Dictionary<string, OpenApiLink>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiCallback"/> Objects.
         /// </summary>
-        public virtual IDictionary<string, OpenApiCallback> Callbacks { get; set; } = new Dictionary<string, OpenApiCallback>();
+        public virtual IDictionary<string, OpenApiCallback>? Callbacks { get; set; } = new Dictionary<string, OpenApiCallback>();
 
         /// <summary>
         /// An object to hold reusable <see cref="OpenApiPathItem"/> Object.
         /// </summary>
-        public virtual IDictionary<string, OpenApiPathItem> PathItems { get; set; } = new Dictionary<string, OpenApiPathItem>();
+        public virtual IDictionary<string, OpenApiPathItem>? PathItems { get; set; } = new Dictionary<string, OpenApiPathItem>();
 
         /// <summary>
         /// This object MAY be extended with Specification Extensions.
         /// </summary>
-        public virtual IDictionary<string, IOpenApiExtension> Extensions { get; set; } = new Dictionary<string, IOpenApiExtension>();
+        public virtual IDictionary<string, IOpenApiExtension>? Extensions { get; set; } = new Dictionary<string, IOpenApiExtension>();
 
         /// <summary>
         /// Parameter-less constructor
@@ -82,7 +83,7 @@ public OpenApiComponents() { }
         /// <summary>
         /// Initializes a copy of an <see cref="OpenApiComponents"/> object
         /// </summary>
-        public OpenApiComponents(OpenApiComponents components)
+        public OpenApiComponents(OpenApiComponents? components)
         {
             Schemas = components?.Schemas != null ? new Dictionary<string, JsonSchema>(components.Schemas) : null;
             Responses = components?.Responses != null ? new Dictionary<string, OpenApiResponse>(components.Responses) : null;