From 9fb60d69f0df191bb609713f045670f2e3c078fb Mon Sep 17 00:00:00 2001
From: tadelesh <tadelesh.shi@live.cn>
Date: Thu, 31 Oct 2024 18:01:53 +0800
Subject: [PATCH] remove useless path parameter from method

---
 .../fix_route_param-2024-9-31-18-1-39.md      |  7 +++
 .../src/http.ts                               | 26 ++++++++---
 .../test/packages/parameters.test.ts          | 44 +++++++++++++++++++
 3 files changed, 71 insertions(+), 6 deletions(-)
 create mode 100644 .chronus/changes/fix_route_param-2024-9-31-18-1-39.md

diff --git a/.chronus/changes/fix_route_param-2024-9-31-18-1-39.md b/.chronus/changes/fix_route_param-2024-9-31-18-1-39.md
new file mode 100644
index 0000000000..d4ff2a14ef
--- /dev/null
+++ b/.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 useless path parameter from method
\ No newline at end of file
diff --git a/packages/typespec-client-generator-core/src/http.ts b/packages/typespec-client-generator-core/src/http.ts
index 05f37afa6a..a49bae7992 100644
--- a/packages/typespec-client-generator-core/src/http.ts
+++ b/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",
@@ -408,12 +409,12 @@ function getSdkHttpResponseAndExceptions(
   context: TCGCContext,
   httpOperation: HttpOperation,
 ): [
-  {
-    responses: SdkHttpResponse[];
-    exceptions: SdkHttpErrorResponse[];
-  },
-  readonly Diagnostic[],
-] {
+    {
+      responses: SdkHttpResponse[];
+      exceptions: SdkHttpErrorResponse[];
+    },
+    readonly Diagnostic[],
+  ] {
   const diagnostics = createDiagnosticCollector();
   const responses: SdkHttpResponse[] = [];
   const exceptions: SdkHttpErrorResponse[] = [];
@@ -628,6 +629,19 @@ function findMapping(
   return undefined;
 }
 
+function filterOutUselessPathParameters(context: TCGCContext, httpOperation: HttpOperation, methodParameters: SdkMethodParameter[]) {
+  // for autoroute with constant or singleton arm resource operation,
+  // some path parameters will be added to route directly with the constant value,
+  // 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;
diff --git a/packages/typespec-client-generator-core/test/packages/parameters.test.ts b/packages/typespec-client-generator-core/test/packages/parameters.test.ts
index c2e64e935e..c7881bbdad 100644
--- a/packages/typespec-client-generator-core/test/packages/parameters.test.ts
+++ b/packages/typespec-client-generator-core/test/packages/parameters.test.ts
@@ -10,6 +10,8 @@ import {
 } from "../../src/interfaces.js";
 import { SdkTestRunner, createSdkTestRunner } from "../test-host.js";
 import { getServiceMethodOfClient, getServiceWithDefaultApiVersion } from "./utils.js";
+import { AzureResourceManagerTestLibrary } from "@azure-tools/typespec-azure-resource-manager/testing";
+import { OpenAPITestLibrary } from "@typespec/openapi/testing";
 
 describe("typespec-client-generator-core: parameters", () => {
   let runner: SdkTestRunner;
@@ -1087,4 +1089,46 @@ 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"]);
+    });
+  });
 });