chore: another round of refactoring

Author: MaggieKimani1

src/Microsoft.OpenApi/Interfaces/IOpenApiVersionService.cs

@@ -18,7 +18,7 @@ internal interface IOpenApiVersionService
         /// <param name="node">document fragment node</param>
         /// <param name="doc">A host document instance.</param>
         /// <returns>Instance of OpenAPIElement</returns>
-        T LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement;
+        T? LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement;
 
         /// <summary>
         /// Converts a generic RootNode instance into a strongly typed OpenApiDocument

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

@@ -46,7 +46,7 @@ public override List<JsonNode> CreateListOfAny()
             return list;
         }
 
-        public override List<T> CreateSimpleList<T>(Func<ValueNode, OpenApiDocument?, T> map, OpenApiDocument? openApiDocument)
+        public override List<T> CreateSimpleList<T>(Func<ValueNode, OpenApiDocument?, T> map, OpenApiDocument openApiDocument)
         {
             if (_nodeList == null)
             {

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

@@ -56,7 +56,7 @@ public virtual Dictionary<string, T> CreateMap<T>(Func<MapNode, OpenApiDocument,
             throw new OpenApiReaderException("Cannot create map from this type of node.", Context);
         }
 
-        public virtual List<T> CreateSimpleList<T>(Func<ValueNode, OpenApiDocument?, T> map, OpenApiDocument? openApiDocument)
+        public virtual List<T> CreateSimpleList<T>(Func<ValueNode, OpenApiDocument?, T> map, OpenApiDocument openApiDocument)
         {
             throw new OpenApiReaderException("Cannot create simple list from this type of node.", Context);
         }

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

@@ -201,10 +201,10 @@ private static string BuildUrl(string? scheme, string? host, string? basePath)
 #if NETSTANDARD2_1_OR_GREATER
             if (!String.IsNullOrEmpty(host) && host.Contains(':', StringComparison.OrdinalIgnoreCase))
 #else
-            if (!String.IsNullOrEmpty(host) && host.Contains(':'))
+            if (!string.IsNullOrEmpty(host) && host is not null && host.Contains(':'))
 #endif
             {
-                var pieces = host?.Split(':');
+                var pieces = host.Split(':');
                 if (pieces is not null)
                 {
                     host = pieces[0];

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

@@ -179,7 +179,7 @@ private static OpenApiRequestBody CreateFormBody(ParsingContext context, List<Op
                             }
                             return schema;
                         }),
-                    Required = new HashSet<string>(formParameters.Where(static p => p.Required).Select(static p => p.Name!).Where(static name => name != null), StringComparer.Ordinal)
+                    Required = new HashSet<string>(formParameters.Where(static p => p.Required && p.Name is not null).Select(static p => p.Name!), StringComparer.Ordinal)
                 }
             };
 

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

@@ -298,9 +298,9 @@ private static void ProcessIn(OpenApiParameter o, ParseNode n, OpenApiDocument h
 
             var isBodyOrFormData = false;
             var paramData = node.Context.GetFromTempStorage<object>(TempStorageKeys.ParameterIsBodyOrFormData);
-            if (paramData is not null)
+            if (paramData is bool boolValue)
             {
-                isBodyOrFormData = (bool)paramData;
+                isBodyOrFormData = boolValue;
             }
 
             if (isBodyOrFormData && !loadRequestBody)

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

@@ -55,9 +55,13 @@ public OpenApiDocument LoadDocument(RootNode rootNode)
             return OpenApiV2Deserializer.LoadOpenApi(rootNode);
         }
 
-        public T LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
+        public T? LoadElement<T>(ParseNode node, OpenApiDocument doc) where T : IOpenApiElement
         {
-            return (T)_loaders[typeof(T)](node, doc)!;
+            if (_loaders.TryGetValue(typeof(T), out var loader) && loader(node, doc) is T result)
+            {
+                return result;
+            }
+            return default;
         }
 
         /// <inheritdoc />

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

@@ -149,7 +149,7 @@ internal static partial class OpenApiV3Deserializer
             },
             {
                 "required",
-                (o, n, doc) => o.Required = new HashSet<string>(n.CreateSimpleList((n2, p) => n2.GetScalarValue(), doc).Where(s => s != null)!)
+                (o, n, doc) => o.Required = new HashSet<string>(n.CreateSimpleList((n2, p) => n2.GetScalarValue(), doc).Where(s => s != null))
             },
             {
                 "enum",

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

@@ -184,7 +184,7 @@ internal static partial class OpenApiV31Deserializer
             },
             {
                 "required",
-                (o, n, doc) => o.Required = new HashSet<string>(n.CreateSimpleList((n2, p) => n2.GetScalarValue(), doc).Where(s => s != null)!)
+                (o, n, doc) => o.Required = new HashSet<string>(n.CreateSimpleList((n2, p) => n2.GetScalarValue(), doc).Where(s => s != null))
             },
             {
                 "enum",

src/Microsoft.OpenApi/Services/OpenApiWorkspace.cs

@@ -205,7 +205,7 @@ public bool RegisterComponentForDocument<T>(OpenApiDocument openApiDocument, T c
                 IOpenApiExample => baseUri + ReferenceType.Example.GetDisplayName() + ComponentSegmentSeparator + id,
                 IOpenApiHeader => baseUri + ReferenceType.Header.GetDisplayName() + ComponentSegmentSeparator + id,
                 IOpenApiSecurityScheme => baseUri + ReferenceType.SecurityScheme.GetDisplayName() + ComponentSegmentSeparator + id,
-                _ => throw new ArgumentException($"Invalid component type {componentToRegister?.GetType().Name}"),
+                _ => throw new ArgumentException($"Invalid component type {componentToRegister!.GetType().Name}"),
             };
 
             return RegisterComponent(location, componentToRegister);