fix(v2): re-export express Response from the https provider

[kyungseopk1m]

Description

onRequest handlers take an express.Response, but src/v2/providers/https.ts only re-exports Request. To annotate a handler parameter you have to add express as a direct dependency just to name the type, even though firebase-functions already depends on it.

v1 does not have this gap: src/v1/cloud-functions.ts re-exports both Request and Response, so functions.Response resolves today. This brings v2 in line.

Response is re-exported from express rather than aliased as export type Response = express.Response, because the express type is generic (Response<ResBody, Locals, StatusCode>) and an alias drops the type parameters, which makes https.Response<MyBody> fail with TS2315.

Fixes #1798.

Code sample

Before, this needs express installed and imported directly:

import { onRequest } from "firebase-functions/v2/https";
import type { Response } from "express";

export const fn = onRequest((req, res: Response<{ ok: boolean }>) => {
  res.json({ ok: true });
});

After:

import { onRequest, type Request, type Response } from "firebase-functions/v2/https";

export const fn = onRequest((req: Request, res: Response<{ ok: boolean }>) => {
  res.json({ ok: true });
});

Scenarios Tested

npm run build and npm run lint pass.

Checked the emitted surface rather than only the source: after building, a probe importing https from lib/v2/index and using https.Response<{ ok: boolean }>, bare https.Response, https.Request, and a full handler signature type checks with tsc --noEmit. The generic form is what fails on an alias, so it is the case that matters here.

Release notes

relnote: fix(v2): re-export the express Response type from firebase-functions/v2/https (#1798)

[gemini-code-assist]

Code Review

This pull request exports the Response type from express in src/v2/providers/https.ts. I have no feedback to provide.

[IzaakGough]

lgtm!

[shettyvarun268]

Nit: Not a blocker at all since its a small change, but we can have a small type assertion test to ensure that Response export does not regress in future refactors.

LGTM otherwise!