Fix: Inline enums properties with default values

.changeset/dry-onions-tie.md

@@ -0,0 +1,5 @@
+---
+"@azure-tools/typespec-autorest": patch
+---
+
+Fix: Inline enums properties with default values as `default` is not allowed next to `$ref`

packages/samples/test/output/core/optional/@azure-tools/typespec-autorest/openapi.json

@@ -95,8 +95,16 @@
           }
         },
         "optionalEnum": {
-          "$ref": "#/definitions/MyEnum",
-          "default": "a"
+          "type": "string",
+          "default": "a",
+          "enum": [
+            "a",
+            "b"
+          ],
+          "x-ms-enum": {
+            "name": "MyEnum",
+            "modelAsString": true
+          }
         }
       }
     },

packages/typespec-autorest/src/openapi.ts

@@ -1722,7 +1722,7 @@ function createOAPIEmitter(
         property.description = description;
       }
 
-      if (prop.default) {
+      if (prop.default && !("$ref" in property)) {
         property.default = getDefaultValue(prop.default);
       }
 
@@ -1793,7 +1793,10 @@ function createOAPIEmitter(
   }
 
   function resolveProperty(prop: ModelProperty, visibility: Visibility): OpenAPI2SchemaProperty {
-    const propSchema = getSchemaOrRef(prop.type, visibility);
+    const propSchema =
+      prop.type.kind === "Enum" && prop.default
+        ? getSchemaForEnum(prop.type)
+        : getSchemaOrRef(prop.type, visibility);
     return applyIntrinsicDecorators(prop, propSchema);
   }
 

packages/typespec-autorest/test/models.test.ts

@@ -273,7 +273,7 @@ describe("typespec-autorest: model definitions", () => {
     });
   });
 
-  it("specify default value on enum property", async () => {
+  it("specify default value on enum property inline the enum", async () => {
     const res = await oapiForModel(
       "Foo",
       `
@@ -287,15 +287,20 @@ describe("typespec-autorest: model definitions", () => {
       }
       `
     );
-
-    ok(res.isRef);
-    ok(res.defs.Foo, "expected definition named Foo");
-    ok(res.defs.MyEnum, "expected definition named MyEnum");
     deepStrictEqual(res.defs.Foo, {
       type: "object",
       properties: {
         optionalEnum: {
-          $ref: "#/definitions/MyEnum",
+          type: "string",
+          enum: ["a-value", "b"],
+          "x-ms-enum": {
+            name: "MyEnum",
+            modelAsString: true,
+            values: [
+              { name: "a", value: "a-value" },
+              { name: "b", value: "b" },
+            ],
+          },
           default: "a-value",
         },
       },

packages/typespec-autorest/test/openapi-output.test.ts

@@ -152,35 +152,6 @@ describe("typespec-autorest: definitions", () => {
     });
   });
 
-  it("specify default value on enum property", async () => {
-    const res = await oapiForModel(
-      "Foo",
-      `
-      model Foo {
-        optionalEnum?: MyEnum = MyEnum.a;
-      };
-
-      enum MyEnum {
-        a: "a-value",
-        b,
-      }
-      `
-    );
-
-    ok(res.isRef);
-    ok(res.defs.Foo, "expected definition named Foo");
-    ok(res.defs.MyEnum, "expected definition named MyEnum");
-    deepStrictEqual(res.defs.Foo, {
-      type: "object",
-      properties: {
-        optionalEnum: {
-          $ref: "#/definitions/MyEnum",
-          default: "a-value",
-        },
-      },
-    });
-  });
-
   it("ignore uninstantiated template types", async () => {
     const res = await openApiFor(
       `