Fixed exposing writer Settings object

Author: darrelmiller

src/Microsoft.OpenApi/Extensions/OpenApiSerializableExtensions.cs

@@ -74,7 +74,9 @@ public static void Serialize<T>(
                     throw new OpenApiException(string.Format(SRResource.OpenApiFormatNotSupported, format));
             }
 
-            element.Serialize(writer, specVersion);
+            writer.Settings.SpecVersion = specVersion;
+
+            element.Serialize(writer);
         }
 
         /// <summary>
@@ -86,6 +88,19 @@ public static void Serialize<T>(
         /// <param name="specVersion">The Open API specification version.</param>
         public static void Serialize<T>(this T element, IOpenApiWriter writer, OpenApiSpecVersion specVersion)
             where T : IOpenApiSerializable
+        {
+            writer.Settings.SpecVersion = specVersion;
+            element.Serialize(writer);
+        }
+
+        /// <summary>
+        /// Serializes the <see cref="IOpenApiSerializable"/> to Open API document using the given specification version and writer.
+        /// </summary>
+        /// <typeparam name="T">the <see cref="IOpenApiSerializable"/></typeparam>
+        /// <param name="element">The Open API element.</param>
+        /// <param name="writer">The output writer.</param>
+        public static void Serialize<T>(this T element, IOpenApiWriter writer)
+            where T : IOpenApiSerializable
         {
             if (element == null)
             {
@@ -97,7 +112,7 @@ public static void Serialize<T>(this T element, IOpenApiWriter writer, OpenApiSp
                 throw Error.ArgumentNull(nameof(writer));
             }
 
-            switch (specVersion)
+            switch (writer.Settings.SpecVersion)
             {
                 case OpenApiSpecVersion.OpenApi3_0:
                     element.SerializeAsV3(writer);
@@ -108,24 +123,12 @@ public static void Serialize<T>(this T element, IOpenApiWriter writer, OpenApiSp
                     break;
 
                 default:
-                    throw new OpenApiException(string.Format(SRResource.OpenApiSpecVersionNotSupported, specVersion));
+                    throw new OpenApiException(string.Format(SRResource.OpenApiSpecVersionNotSupported, writer.Settings.SpecVersion));
             }
 
             writer.Flush();
         }
 
-        /// <summary>
-        /// Serializes the <see cref="IOpenApiSerializable"/> to Open API document using the given specification version and writer.
-        /// </summary>
-        /// <typeparam name="T">the <see cref="IOpenApiSerializable"/></typeparam>
-        /// <param name="element">The Open API element.</param>
-        /// <param name="writer">The output writer.</param>
-        public static void Serialize<T>(this T element, IOpenApiWriter writer)
-            where T : IOpenApiSerializable
-        {
-            element.Serialize(writer, writer.Settings.SpecVersion);
-        }
-
         /// <summary>
         /// Serializes the <see cref="IOpenApiSerializable"/> to the Open API document as a string in JSON format.
         /// </summary>

src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs

@@ -51,7 +51,12 @@ public OpenApiWriterBase(TextWriter textWriter, OpenApiSerializerSettings settin
         /// <summary>
         /// Returns the settings being used the Writer for controlling serialization
         /// </summary>
-        public OpenApiSerializerSettings Settings { get; }
+        public OpenApiSerializerSettings Settings {
+            get
+            {
+                return _settings; 
+            }
+        }
 
         /// <summary>
         /// Base Indentation Level.

src/Microsoft.OpenApi/Writers/OpenApiYamlWriter.cs

@@ -15,7 +15,7 @@ public class OpenApiYamlWriter : OpenApiWriterBase
         /// </summary>
         /// <param name="textWriter">The text writer.</param>
         public OpenApiYamlWriter(TextWriter textWriter)
-            : this(textWriter, new OpenApiSerializerSettings())
+            : this(textWriter, new OpenApiSerializerSettings() { Format = OpenApiFormat.Yaml })
         {
         }