Try work with named unions

packages/cadl-typescript/package.json

@@ -40,10 +40,10 @@
     "ts-node": "^10.7.0",
     "typescript": "~4.8.0",
     "prettier": "~2.7.1",
-    "@azure-tools/cadl-ranch-specs": "~0.7.0",
+    "@azure-tools/cadl-ranch-specs": "~0.8.0",
     "@cadl-lang/versioning": "~0.40.0",
     "@azure-tools/cadl-ranch-expect": "^0.1.16",
-    "@azure-tools/cadl-ranch": "~0.3.0",
+    "@azure-tools/cadl-ranch": "~0.3.1",
     "chalk": "^4.0.0",
     "@azure-rest/core-client": "^1.1.0",
     "@azure/core-auth": "^1.3.2",

packages/cadl-typescript/src/modelUtils.ts

@@ -31,7 +31,8 @@ import {
   Type,
   Union,
   isNullType,
-  Scalar
+  Scalar,
+  UnionVariant
 } from "@cadl-lang/compiler";
 import { reportDiagnostic } from "./lib.js";
 import {
@@ -85,6 +86,8 @@ export function getSchemaForType(
     return schema;
   } else if (type.kind === "Union") {
     return getSchemaForUnion(program, type, usage);
+  } else if (type.kind === "UnionVariant") {
+    return getSchemaForUnionVariant(program, type, usage);
   } else if (type.kind === "Enum") {
     return getSchemaForEnum(program, type);
   } else if (type.kind === "Scalar") {
@@ -146,26 +149,39 @@ function getSchemaForUnion(
   union: Union,
   usage?: SchemaContext[]
 ) {
-  const nonNullOptions = union.options.filter((t) => !isNullType(t));
-  const nullable = union.options.length != nonNullOptions.length;
+  const variants = Array.from(union.variants.values());
+  const nonNullOptions = variants.filter((t) => !isNullType(t.type));
+  const nullable = variants.length !== nonNullOptions.length;
   if (nonNullOptions.length === 0 || nonNullOptions[0] === undefined) {
     reportDiagnostic(program, { code: "union-null", target: union });
     return {};
   }
 
   const values = [];
 
-  for (const option of nonNullOptions) {
+  for (const variant of nonNullOptions) {
     // We already know it's not a model type
-    values.push(getSchemaForType(program, option, usage));
+    values.push(getSchemaForType(program, variant.type, usage));
   }
 
   const schema: any = {};
   if (values.length > 0) {
     schema.enum = values;
-    schema.type = values
-      .map((item) => `${getTypeName(item) ?? item}`)
+    const unionAlias = values
+      .map((item) => `${getTypeName(item, [SchemaContext.Input]) ?? item}`)
       .join(" | ");
+    const outputUnionAlias = values
+      .map((item) => `${getTypeName(item, [SchemaContext.Output]) ?? item}`)
+      .join(" | ");
+    schema.type = !union.expression && union.name ? union.name : unionAlias;
+    if (!union.expression) {
+      schema.name = union.name;
+      schema.type = "object";
+      schema.typeName = union.name;
+      schema.outputTypeName = union.name + "Output";
+      schema.alias = unionAlias;
+      schema.outputAlias = outputUnionAlias;
+    }
   }
   if (nullable) {
     schema["required"] = false;
@@ -174,6 +190,14 @@ function getSchemaForUnion(
   return schema;
 }
 
+function getSchemaForUnionVariant(
+  program: Program,
+  variant: UnionVariant,
+  usage?: SchemaContext[]
+): Schema {
+  return getSchemaForType(program, variant, usage);
+}
+
 // An openapi "string" can be defined in several different ways in Cadl
 function isOasString(type: Type): boolean {
   if (type.kind === "String") {
@@ -835,9 +859,9 @@ function getSchemaForStdScalar(program: Program, cadlType: Scalar) {
   }
 }
 
-export function getTypeName(schema: Schema): string {
+export function getTypeName(schema: Schema, usage?: SchemaContext[]): string {
   // TODO: Handle more cases
-  return getPriorityName(schema) ?? schema.type ?? "any";
+  return getPriorityName(schema, usage) ?? schema.type ?? "any";
 }
 
 export function getImportedModelName(schema: Schema): string[] | undefined {
@@ -857,8 +881,12 @@ export function getImportedModelName(schema: Schema): string[] | undefined {
   }
 }
 
-function getPriorityName(schema: Schema): string {
-  return schema.outputTypeName ?? schema.typeName ?? schema.name;
+function getPriorityName(schema: Schema, usage?: SchemaContext[]): string {
+  return usage &&
+    usage.includes(SchemaContext.Input) &&
+    !usage.includes(SchemaContext.Output)
+    ? schema.typeName ?? schema.name
+    : schema.outputTypeName ?? schema.typeName ?? schema.name;
 }
 function getDictionaryValueName(schema: DictionarySchema): string | undefined {
   return schema.outputValueTypeName ?? schema.valueTypeName ?? undefined;

packages/cadl-typescript/src/transform/transformSchemas.ts

@@ -137,6 +137,30 @@ export function transformSchemas(
           }
           getGeneratedModels(prop[1].type, context);
         }
+        if (
+          prop[1].type.kind === "Union" &&
+          (!program.stateMap(modelKey).get(prop[1].type) ||
+            !program.stateMap(modelKey).get(prop[1].type)?.includes(context))
+        ) {
+          const variants = Array.from(prop[1].type.variants.values());
+          let hasModels = false;
+          for (const variant of variants) {
+            if (
+              variant.type.kind === "Model" &&
+              (!program.stateMap(modelKey).get(variant.type) ||
+                !program
+                  .stateMap(modelKey)
+                  .get(variant.type)
+                  ?.includes(context))
+            ) {
+              hasModels = true;
+              getGeneratedModels(variant.type, context);
+            }
+          }
+          if (hasModels) {
+            setModelMap(prop[1].type, context);
+          }
+        }
       }
       const baseModel = model.baseModel;
       if (

packages/cadl-typescript/test/commands/cadl-ranch-list.ts

@@ -75,5 +75,9 @@ export const cadls: CadlRanchConfig[] = [
   {
     outputPath: "specialWords",
     inputPath: "special-words"
+  },
+  {
+    outputPath: "unions",
+    inputPath: "unions"
   }
 ];

packages/cadl-typescript/test/integration/generated/unions/cadl-project.yaml

@@ -0,0 +1,11 @@
+emitters:
+  "../../../../../../../../../../packages/cadl-typescript/dist/src/index.js":
+    generateMetadata: false
+    generateTest: false
+    addCredentials: false
+    azureSdkForJs: false
+    isCadlTest: true
+    title: UnionsClient
+    packageDetails:
+      name: "@msinternal/unions"
+      description: "Unions Test Service"