Adjust discriminator to reduce duplicated props

src/typespec-aaz/src/convertor.ts

@@ -895,8 +895,6 @@ function convertModel2CMDObjectSchemaBase(
       properties[propertyName] = discriminatorProperty;
     }
 
-    const discProperty = properties[propertyName] as CMDStringSchema;
-
     const derivedModels = payloadModel.derivedModels.filter(includeDerivedModel);
     for (const child of derivedModels) {
       const childDiscriminatorValue = getDiscriminatorInfo(context, child);
@@ -905,12 +903,6 @@ function convertModel2CMDObjectSchemaBase(
         if (disc) {
           object.discriminators ??= [];
           object.discriminators.push(disc);
-          discProperty.enum ??= {
-            items: [],
-          };
-          discProperty.enum.items.push({
-            value: childDiscriminatorValue.value,
-          });
         }
       }
     }
@@ -1008,6 +1000,10 @@ function convertModel2CMDObjectDiscriminator(
     }
 
     const jsonName = getJsonName(context, prop);
+    if (jsonName === discriminatorInfo.propertyName) {
+      // if this property is a discriminator property, remove it as autorest
+      continue;
+    }
     let schema = convert2CMDSchema(
       {
         ...context,
@@ -1016,6 +1012,7 @@ function convertModel2CMDObjectDiscriminator(
       prop,
       jsonName,
     );
+
     if (schema) {
       if (isReadonlyProperty(context.program, prop)) {
         schema.readOnly = true;

src/typespec-aaz/test/discriminator.test.ts

@@ -0,0 +1,61 @@
+import { TestHost, BasicTestRunner } from "@typespec/compiler/testing";
+import { describe, expect, it, beforeEach } from "vitest";
+import { createTypespecAazTestHost, createTypespecAazTestRunner, compileTypespecAAZOperations } from "./test-aaz.js";
+import { ModelVar, generateCompileArmResourceTemplate, findObjectsWithKey } from "./util.js";
+
+describe("discriminator parsing", () => {
+  let host: TestHost;
+  let runner: BasicTestRunner;
+
+  beforeEach(async () => {
+    host = await createTypespecAazTestHost();
+    runner = await createTypespecAazTestRunner(host);
+  });
+
+  it("validate discriminator value", async () => {
+    const modelTmp: ModelVar = {
+      modelKey: "targetValue",
+      modelContent: "TargetResourceConfigurations",
+      isComposite: true,
+      appendModel: `
+      union ResourceKind {
+        string,
+        FunctionsFlexConsumption: "FunctionsFlexConsumption",
+      }
+
+      model FunctionFlexConsumptionResourceConfiguration {
+        instanceMemoryMB: int64;
+        httpConcurrency?: int64;
+      }
+
+      @discriminator("kind")
+      model TargetResourceConfigurations {
+        @visibility(Lifecycle.Create, Lifecycle.Read)
+        kind: ResourceKind;
+      }
+
+      model FunctionFlexConsumptionTargetResourceConfigurations
+        extends TargetResourceConfigurations {
+        kind: ResourceKind.FunctionsFlexConsumption;
+        configurations?: Record<FunctionFlexConsumptionResourceConfiguration>;
+      }
+      `,
+    };
+
+    const code: string = generateCompileArmResourceTemplate(modelTmp);
+    const result = await compileTypespecAAZOperations(
+      code,
+      {
+        "operation": "get-resources-operations",
+        "api-version": "A",
+        "resources": ["/subscriptions/{}/resourcegroups/{}/providers/microsoft.mock/mockresources/{}"],
+      },
+      runner,
+    );
+    const resultObj = JSON.parse(result!);
+    expect(Array.isArray(resultObj)).toBe(true);
+    expect(resultObj.length).toBe(1);
+    const targetObj = findObjectsWithKey(resultObj[0].pathItem.get.read.http.responses, "targetValue");
+    await expect(JSON.stringify(targetObj, null, 2)).toMatchFileSnapshot("./snapshots/discriminator-prop.json");
+  });
+});

src/typespec-aaz/test/snapshots/discriminator-prop.json

@@ -0,0 +1,47 @@
+{
+  "type": "object",
+  "discriminators": [
+    {
+      "property": "kind",
+      "value": "FunctionsFlexConsumption",
+      "props": [
+        {
+          "type": "object",
+          "additionalProps": {
+            "item": {
+              "type": "object",
+              "props": [
+                {
+                  "type": "integer64",
+                  "name": "instanceMemoryMB",
+                  "required": true
+                },
+                {
+                  "type": "integer64",
+                  "name": "httpConcurrency"
+                }
+              ]
+            }
+          },
+          "name": "configurations"
+        }
+      ]
+    }
+  ],
+  "props": [
+    {
+      "type": "string",
+      "enum": {
+        "items": [
+          {
+            "value": "FunctionsFlexConsumption"
+          }
+        ]
+      },
+      "name": "kind",
+      "required": true
+    }
+  ],
+  "name": "targetValue",
+  "required": true
+}