BREAKING: Break TS build that uses functions.config() (#1757)

Type out `functions.config()` API. Use of `functions.config()` API should now cause a BUILD error at compile time. ```ts import * as functions from "firebase-functions"; import {onRequest} from "firebase-functions/https"; import * as logger from "firebase-functions/logger"; const cfg = functions.config() export const helloWorld = onRequest((request, response) => { logger.info("Hello logs!", cfg); response.send("Hello from Firebase!"); }); ``` ```bash $ npm run build > build > tsc src/index.ts:5:23 - error TS2349: This expression is not callable. Type 'never' has no call signatures. 5 const cfg = functions.config() ~~~~~~ Found 1 error in src/index.ts:5 ```

Author: taeold

spec/v1/config.spec.ts

@@ -26,11 +26,14 @@ import { config } from "../../src/v1/config";
 
 describe("config()", () => {
  it("throws an error with migration guidance", () => {
- expect(config).to.throw(
+ expect(() => {
+ // @ts-expect-error - config is deprecated and typed as never to cause a build error
+ config();
+ }).to.throw(
  Error,
  "functions.config() has been removed in firebase-functions v7. " +
  "Migrate to environment parameters using the params module. " +
  "Migration guide: https://firebase.google.com/docs/functions/config-env#migrate-config"
  );
  });
-});
+});

src/v1/config.ts

@@ -27,10 +27,10 @@ export { firebaseConfig } from "../common/config";
  * Migrate to environment parameters using the `params` module immediately.
  * Migration guide: https://firebase.google.com/docs/functions/config-env#migrate-config
  */
-export function config(): Record<string, any> {
+export const config: never = (() => {
  throw new Error(
  "functions.config() has been removed in firebase-functions v7. " +
  "Migrate to environment parameters using the params module. " +
  "Migration guide: https://firebase.google.com/docs/functions/config-env#migrate-config"
  );
-}
+}) as never;