Fix issue: OpenAPI 3 Emitter failed to check type of termsOfService i…

…n @info (#4483)

[issue 3885](#3885)

---------

Co-authored-by: Kyle Zhang <v-zhanh@microsoft.com>
Co-authored-by: Timothee Guerin <timothee.guerin@outlook.com>

.chronus/changes/termsOfServiceUrlCheck-2024-8-23-12-59-15.md

@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi"
+---
+
+`@info` decorator validate `termsOfService` is a valid url

packages/openapi/src/decorators.ts

@@ -185,6 +185,11 @@ export const $info: InfoDecorator = (
   if (data === undefined) {
     return;
   }
+  if (data.termsOfService) {
+    if (!validateIsUri(context, data.termsOfService, "TermsOfService")) {
+      return;
+    }
+  }
   setInfo(context.program, entity, data);
 };
 
@@ -214,3 +219,17 @@ export function resolveInfo(program: Program, entity: Namespace): AdditionalInfo
 function omitUndefined<T extends Record<string, unknown>>(data: T): T {
   return Object.fromEntries(Object.entries(data).filter(([k, v]) => v !== undefined)) as any;
 }
+
+function validateIsUri(context: DecoratorContext, url: string, propertyName: string) {
+  try {
+    new URL(url);
+    return true;
+  } catch {
+    reportDiagnostic(context.program, {
+      code: "not-url",
+      target: context.getArgumentTarget(0)!,
+      format: { property: propertyName, value: url },
+    });
+    return false;
+  }
+}

packages/openapi/src/lib.ts

@@ -16,6 +16,12 @@ export const $lib = createTypeSpecLibrary({
         parameter: paramMessage`Duplicate parameter key: '${"value"}'. Check @friendlyName decorators and overlap with types in TypeSpec or service namespace.`,
       },
     },
+    "not-url": {
+      severity: "error",
+      messages: {
+        default: paramMessage`${"property"}: ${"value"} is not a valid URL.`,
+      },
+    },
   },
 });
 

packages/openapi/test/decorators.test.ts

@@ -152,6 +152,18 @@ describe("openapi: decorators", () => {
   });
 
   describe("@info", () => {
+    it("emit diagnostic if termsOfService is not a valid url", async () => {
+      const diagnostics = await runner.diagnose(`
+        @info({termsOfService:"notvalidurl"})
+        @test namespace Service {}
+      `);
+
+      expectDiagnostics(diagnostics, {
+        code: "@typespec/openapi/not-url",
+        message: "TermsOfService: notvalidurl is not a valid URL.",
+      });
+    });
+
     it("emit diagnostic if use on non namespace", async () => {
       const diagnostics = await runner.diagnose(`
         @info({})