From b7e45f008ff7db2f2a2a2ce91c3d139bc596652e Mon Sep 17 00:00:00 2001
From: Timothee Guerin <tiguerin@microsoft.com>
Date: Mon, 22 Apr 2024 18:48:07 -0700
Subject: [PATCH] Fix `@path` param mapping when spreading a record in
 operation parameters (#3190)

fix #3051
---
 ...-param-mapping-record-2024-3-18-16-17-3.md |  8 ++++++
 packages/http/src/lib.ts                      |  2 +-
 packages/http/src/metadata.ts                 |  2 +-
 packages/http/test/routes.test.ts             | 27 +++++++++++++++++++
 packages/http/test/test-host.ts               |  8 ++++++
 5 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 .chronus/changes/fix-path-param-mapping-record-2024-3-18-16-17-3.md

diff --git a/.chronus/changes/fix-path-param-mapping-record-2024-3-18-16-17-3.md b/.chronus/changes/fix-path-param-mapping-record-2024-3-18-16-17-3.md
new file mode 100644
index 0000000000..288304c562
--- /dev/null
+++ b/.chronus/changes/fix-path-param-mapping-record-2024-3-18-16-17-3.md
@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/http"
+---
+
+Fix `@path` param mapping when spreading a record in operation parameters
diff --git a/packages/http/src/lib.ts b/packages/http/src/lib.ts
index fa1ff2f18a..8d8ed02b7a 100644
--- a/packages/http/src/lib.ts
+++ b/packages/http/src/lib.ts
@@ -18,7 +18,7 @@ export const $lib = createTypeSpecLibrary({
     "missing-path-param": {
       severity: "error",
       messages: {
-        default: paramMessage`Path contains parameter ${"param"} but wasn't found in given parameters`,
+        default: paramMessage`Route reference parameter '${"param"}' but wasn't found in operation parameters`,
       },
     },
     "optional-path-param": {
diff --git a/packages/http/src/metadata.ts b/packages/http/src/metadata.ts
index 2108d89a23..2732016353 100644
--- a/packages/http/src/metadata.ts
+++ b/packages/http/src/metadata.ts
@@ -235,7 +235,7 @@ export function gatherMetadata(
   rootMapOut?: Map<ModelProperty, ModelProperty>
 ): Set<ModelProperty> {
   const metadata = new Map<string, ModelProperty>();
-  if (type.kind !== "Model" || type.indexer || type.properties.size === 0) {
+  if (type.kind !== "Model" || type.properties.size === 0) {
     return new Set();
   }
 
diff --git a/packages/http/test/routes.test.ts b/packages/http/test/routes.test.ts
index 055c05688f..d5bdd454c4 100644
--- a/packages/http/test/routes.test.ts
+++ b/packages/http/test/routes.test.ts
@@ -6,6 +6,7 @@ import { HttpOperation, getRoutePath } from "../src/index.js";
 import {
   compileOperations,
   createHttpTestRunner,
+  diagnoseOperations,
   getOperations,
   getRoutesFor,
 } from "./test-host.js";
@@ -150,6 +151,32 @@ describe("http: routes", () => {
     });
   });
 
+  describe("@route path parameters mapping", () => {
+    it("maps route interpolated params to the operation param", async () => {
+      const routes = await getRoutesFor(
+        `@route("/foo/{myParam}/") op test(@path myParam: string): void;`
+      );
+      deepStrictEqual(routes, [{ verb: "get", path: "/foo/{myParam}", params: ["myParam"] }]);
+    });
+
+    it("maps route interpolated params to the operation param when operation spread items", async () => {
+      const routes = await getRoutesFor(
+        `@route("/foo/{myParam}/") op test(@path myParam: string, ...Record<string>): void;`
+      );
+      deepStrictEqual(routes, [{ verb: "post", path: "/foo/{myParam}", params: ["myParam"] }]);
+    });
+
+    it("emit diagnostic if interpolated param is missing in param list", async () => {
+      const diagnostics = await diagnoseOperations(
+        `@route("/foo/{myParam}/") op test(@path other: string): void;`
+      );
+      expectDiagnostics(diagnostics, {
+        code: "@typespec/http/missing-path-param",
+        message: "Route reference parameter 'myParam' but wasn't found in operation parameters",
+      });
+    });
+  });
+
   describe("path parameters when no explicit @route", () => {
     it("uses the name of the parameter by default and wraps in {}", async () => {
       const routes = await getRoutesFor(`op test(@path myParam: string): void;`);
diff --git a/packages/http/test/test-host.ts b/packages/http/test/test-host.ts
index 04416003cd..0280b7588a 100644
--- a/packages/http/test/test-host.ts
+++ b/packages/http/test/test-host.ts
@@ -81,6 +81,14 @@ export async function compileOperations(
   return [details, diagnostics];
 }
 
+export async function diagnoseOperations(
+  code: string,
+  routeOptions?: RouteResolutionOptions
+): Promise<readonly Diagnostic[]> {
+  const [_, diagnostics] = await compileOperations(code, routeOptions);
+  return diagnostics;
+}
+
 export async function getOperationsWithServiceNamespace(
   code: string,
   routeOptions?: RouteResolutionOptions