add flags to NextApiHandler and WrappedNextApiHandler types

Author: lobsterkatie

packages/nextjs/src/utils/withSentry.ts

@@ -12,7 +12,7 @@ import {
 import * as domain from 'domain';
 import { NextApiRequest, NextApiResponse } from 'next';
 
-// These are the same as the official `NextApiHandler` type, except
+// The `NextApiHandler` and `WrappedNextApiHandler` types are the same as the official `NextApiHandler` type, except:
 //
 // a) The wrapped version returns only promises, because wrapped handlers are always async.
 //
@@ -26,13 +26,23 @@ import { NextApiRequest, NextApiResponse } from 'next';
 // type here would break the test app's build, because it would set up a situation in which the linked SDK's
 // `withSentry` would refer to one version of the type (from the local repo's `node_modules`) while any typed handler in
 // the test app would refer to the other version of the type (from the test app's `node_modules`). By using a custom
-// version of the type compatible with both the old and new official versions, we can use any Next version we want in
-// a test app without worrying about type errors.
-export type NextApiHandler = (
-  req: NextApiRequest,
-  res: NextApiResponse,
-) => void | Promise<void> | unknown | Promise<unknown>;
-export type WrappedNextApiHandler = (req: NextApiRequest, res: NextApiResponse) => Promise<void> | Promise<unknown>;
+// version of the type compatible with both the old and new official versions, we can use any Next version we want in a
+// test app without worrying about type errors.
+//
+// c) These have internal SDK flags which the official Next types obviously don't have, one to allow our auto-wrapping
+// function, `withSentryAPI`, to pass the parameterized route into `withSentry`, and the other to prevent a manually
+// wrapped route from being wrapped again by the auto-wrapper.
+
+export type NextApiHandler = {
+  __sentry_route__?: string;
+  (req: NextApiRequest, res: NextApiResponse): void | Promise<void> | unknown | Promise<unknown>;
+};
+
+export type WrappedNextApiHandler = {
+  __sentry_route__?: string;
+  __sentry_wrapped__?: boolean;
+  (req: NextApiRequest, res: NextApiResponse): Promise<void> | Promise<unknown>;
+};
 
 export type AugmentedNextApiResponse = NextApiResponse & {
   __sentryTransaction?: Transaction;