[tcgc] remove unused path parameter from method

.chronus/changes/fix_route_param-2024-9-31-18-1-39.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@azure-tools/typespec-client-generator-core"
+---
+
+remove unused path parameter from method

packages/typespec-client-generator-core/src/http.ts

@@ -85,6 +85,7 @@ export function getSdkHttpOperation(
   const parameters = diagnostics.pipe(
     getSdkHttpParameters(context, httpOperation, methodParameters, responsesWithBodies[0]),
   );
+  filterOutUselessPathParameters(context, httpOperation, methodParameters);
   return diagnostics.wrap({
     __raw: httpOperation,
     kind: "http",
@@ -628,6 +629,31 @@ function findMapping(
   return undefined;
 }
 
+function filterOutUselessPathParameters(
+  context: TCGCContext,
+  httpOperation: HttpOperation,
+  methodParameters: SdkMethodParameter[],
+) {
+  // there are some cases that method path parameter is not in operation:
+  // 1. autoroute with constant parameter
+  // 2. singleton arm resource name
+  // 3. visibility mis-match
+  // so we will remove the method parameter for consistent
+  for (let i = 0; i < methodParameters.length; i++) {
+    const param = methodParameters[i];
+    if (
+      param.__raw &&
+      isPathParam(context.program, param.__raw) &&
+      httpOperation.parameters.parameters.filter(
+        (p) => p.type === "path" && p.name === getWireName(context, param.__raw!),
+      ).length === 0
+    ) {
+      methodParameters.splice(i, 1);
+      i--;
+    }
+  }
+}
+
 function findRootSourceProperty(property: ModelProperty): ModelProperty {
   while (property.sourceProperty) {
     property = property.sourceProperty;

packages/typespec-client-generator-core/test/package.test.ts

@@ -350,10 +350,10 @@ describe("typespec-client-generator-core: package", () => {
       const method = getServiceMethodOfClient(sdkPackage);
       strictEqual(method.name, "create");
       strictEqual(method.kind, "basic");
-      strictEqual(method.parameters.length, 5);
+      strictEqual(method.parameters.length, 4);
       deepStrictEqual(
         method.parameters.map((x) => x.name),
-        ["id", "weight", "color", "contentType", "accept"],
+        ["weight", "color", "contentType", "accept"],
       );
 
       const bodyParameter = method.operation.bodyParam;

packages/typespec-client-generator-core/test/packages/parameters.test.ts

@@ -1,4 +1,6 @@
 import { AzureCoreTestLibrary } from "@azure-tools/typespec-azure-core/testing";
+import { AzureResourceManagerTestLibrary } from "@azure-tools/typespec-azure-resource-manager/testing";
+import { OpenAPITestLibrary } from "@typespec/openapi/testing";
 import { deepStrictEqual, ok, strictEqual } from "assert";
 import { beforeEach, describe, it } from "vitest";
 import {
@@ -1087,4 +1089,52 @@ describe("typespec-client-generator-core: parameters", () => {
       strictEqual(method.operation.bodyParam?.serializedName, "body");
     });
   });
+
+  describe("method parameter not used in operation", () => {
+    it("autoroute with constant", async () => {
+      await runner.compileWithBuiltInService(`
+          @autoRoute
+          op test(@path param: "test"): void;
+        `);
+      const sdkPackage = runner.context.sdkPackage;
+      const method = getServiceMethodOfClient(sdkPackage);
+      strictEqual(method.parameters.length, 0);
+      strictEqual(method.operation.parameters.length, 0);
+      strictEqual(method.operation.uriTemplate, "/test");
+    });
+
+    it("singleton resource", async () => {
+      const runnerWithArm = await createSdkTestRunner({
+        librariesToAdd: [AzureResourceManagerTestLibrary, AzureCoreTestLibrary, OpenAPITestLibrary],
+        autoUsings: ["Azure.ResourceManager", "Azure.Core"],
+        emitterName: "@azure-tools/typespec-java",
+      });
+      await runnerWithArm.compileWithBuiltInAzureResourceManagerService(`
+        @singleton("default")
+        model SingletonTrackedResource is TrackedResource<SingletonTrackedResourceProperties> {
+          ...ResourceNameParameter<SingletonTrackedResource>;
+        }
+
+        model SingletonTrackedResourceProperties {
+          description?: string;
+        }
+
+        @armResourceOperations
+        interface Singleton {
+          createOrUpdate is ArmResourceCreateOrReplaceAsync<SingletonTrackedResource>;
+        }
+      `);
+
+      const sdkPackage = runnerWithArm.context.sdkPackage;
+      const method = getServiceMethodOfClient(sdkPackage);
+      deepStrictEqual(
+        method.parameters.map((p) => p.name),
+        ["resourceGroupName", "resource", "contentType", "accept"],
+      );
+      deepStrictEqual(
+        method.operation.parameters.map((p) => p.name),
+        ["apiVersion", "subscriptionId", "resourceGroupName", "contentType", "accept"],
+      );
+    });
+  });
 });