Should not flatten poloymophic class and should not check null for required value type (#1242)

powershell/plugins/sdk-create-inline-properties.ts

@@ -479,7 +479,7 @@ async function handlePayloadFlatteningThreshold(state: State): Promise<void> {
           const bodyParameterSchema = bodyParameter.schema;
           if (bodyParameterSchema.type === SchemaType.Object) {
             const virtualProperties = getAllPublicVirtualProperties(bodyParameterSchema.language.default.virtualProperties).filter(vp => !vp.readOnly && !(vp.required && (vp.property.schema.type === SchemaType.Constant || helper.IsConstantEnumProperty(vp))));
-            if (virtualProperties.length <= payloadFlatteningThreshold) {
+            if (virtualProperties.length <= payloadFlatteningThreshold && !(bodyParameter.schema.type === SchemaType.Object && ((<ObjectSchema>bodyParameter.schema).discriminator || (<ObjectSchema>bodyParameter.schema).discriminatorValue))) {
               bodyParameter.extensions = bodyParameter.extensions || {};
               bodyParameter.extensions['x-ms-client-flatten'] = true;
             }

powershell/resources/templates/methodBodyRestCall.ejs

@@ -57,14 +57,22 @@ if (method.extensions && method.extensions['x-ms-request-id']) {
 <% (method.requests[0].parameters || []).filter(p=>p.protocol.http.in == 'body').forEach(function(parameter){-%>
 <%if(parameter.extensions && parameter.extensions['x-ms-client-flatten']) {-%>
             <%-parameter.schema.language.default.name%> <%-parameter.language.default.name%> = new <%-parameter.schema.language.default.name%>();
-<% var vps = project.helper.GetAllPublicVirtualProperties(parameter.schema.language.default.virtualProperties).filter(vp => !project.helper.IsConstantEnumProperty(vp) && !vp.readOnly)-%>
-            if(<%-vps.map(vp=>`${vp.property.language.default.name} != null`).join('||')%>)
+<% var vps = project.helper.GetAllPublicVirtualProperties(parameter.schema.language.default.virtualProperties).filter(vp => !project.helper.IsConstantEnumProperty(vp) && !vp.readOnly)
+   var vpsWithNullCheck = vps.filter(virtualProperty => project.helper.IsNullCheckRequiredForVirtualProperty(virtualProperty));
+   var vpsWithoutNullCheck = vps.filter(virtualProperty => !project.helper.IsNullCheckRequiredForVirtualProperty(virtualProperty));
+-%>
+<% if(vpsWithNullCheck.length > 0) {-%>
+            if(<%-vpsWithNullCheck.map(vp=>`${vp.property.language.default.name} != null`).join('||')%>)
             {
-<%vps.forEach(function(vp) {-%>
+<%vpsWithNullCheck.forEach(function(vp) {-%>
                 <%-parameter.language.default.name%>.<%-vp.property.language.csharp.name%> = <%-vp.property.language.default.name%>;
 <%});-%>
             }
 <%}-%>
+<%vpsWithoutNullCheck.forEach(function(vp) {-%>
+            <%-parameter.language.default.name%>.<%-vp.property.language.csharp.name%> = <%-vp.property.language.default.name%>;
+<%});-%>
+<%}-%>
 <% });-%>
 <%}-%>
             // Tracing

powershell/sdk/utility.ts

@@ -304,6 +304,10 @@ export class Helper {
     return ref + '.SerializationSettings';
   }
 
+  public IsNullCheckRequiredForVirtualProperty(virtualProperty: VirtualProperty): boolean {
+    return !((this.IsValueType(virtualProperty.property.schema.type) || (virtualProperty.property.schema.type === SchemaType.SealedChoice && ((<SealedChoiceSchema>virtualProperty.property.schema).choiceType.type !== SchemaType.String || (virtualProperty.property.schema.extensions && !virtualProperty.property.schema.extensions['x-ms-model-as-string'])))) && (virtualProperty.required || virtualProperty.property.nullable === false));
+  }
+
   public CamelCase(str: string): string {
     // str = str.replace(/(?:^\w|[A-Z]|\b\w)/g, function (word, index) {
     //   return index === 0 ? word.toLowerCase() : word.toUpperCase();