Remove the server.enhanceMiddleware deprecation warning (#2091)

Author: robhogan

docs/Configuration.md

@@ -789,7 +789,7 @@ Has no effect.
 
 Type: `(Middleware, MetroServer) => Middleware | connect.Server`
 
-A function that allows attaching custom [`connect`](https://www.npmjs.com/package/connect) middleware to Metro. Metro logs a deprecation warning when this option is set to anything other than its default. Use [`unstable_middleware`](#unstable_middleware-experimental) or [`unstable_priorityMiddleware`](#unstable_prioritymiddleware-experimental) instead, and [`unstable_onServerCreated`](#unstable_onservercreated-experimental) to access the Metro server instance.
+A function that allows attaching custom [`connect`](https://www.npmjs.com/package/connect) middleware to Metro. Use [`unstable_middleware`](#unstable_middleware-experimental) or [`unstable_priorityMiddleware`](#unstable_prioritymiddleware-experimental) instead, and [`unstable_onServerCreated`](#unstable_onservercreated-experimental) to access the Metro server instance.
 
 For example:
 

packages/metro-config/src/defaults/defaults.js

@@ -9,7 +9,7 @@
  * @oncall react_native
  */
 
-import type {ConfigT, PerfLogger, RootPerfLogger} from '../types';
+import type {PerfLogger, RootPerfLogger} from '../types';
 
 export {default as defaultCreateModuleIdFactory} from './createModuleIdFactory';
 
@@ -63,10 +63,6 @@ export const platforms: Array<string> = ['ios', 'android', 'windows', 'web'];
 
 export const DEFAULT_METRO_MINIFIER_PATH = 'metro-minify-terser';
 
-// Metro warns about `server.enhanceMiddleware` unless it is this function.
-export const defaultEnhanceMiddleware: ConfigT['server']['enhanceMiddleware'] =
-  (middleware, _server) => middleware;
-
 export const noopPerfLoggerFactory = (): RootPerfLogger => {
   class Logger {
     start() {}

packages/metro-config/src/defaults/index.js

@@ -17,7 +17,6 @@ import {
   assetExts,
   assetResolutions,
   defaultCreateModuleIdFactory,
-  defaultEnhanceMiddleware,
   noopPerfLoggerFactory,
   platforms,
   sourceExts,
@@ -76,7 +75,7 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
   },
 
   server: {
-    enhanceMiddleware: defaultEnhanceMiddleware,
+    enhanceMiddleware: (middleware, _) => middleware,
     forwardClientLogs: true,
     port: 8081,
     rewriteRequestUrl: url => url,

packages/metro/src/index.flow.js

@@ -49,7 +49,6 @@ import {
   mergeConfig,
   resolveConfig,
 } from 'metro-config';
-import {defaultEnhanceMiddleware} from 'metro-config/private/defaults/defaults';
 import {Terminal} from 'metro-core';
 import fs from 'node:fs';
 import http from 'node:http';
@@ -249,14 +248,6 @@ export const createConnectMiddleware = async function (
 
   // Enhance the resulting middleware using the config options
   if (config.server.enhanceMiddleware) {
-    if (config.server.enhanceMiddleware !== defaultEnhanceMiddleware) {
-      logDeprecationWarning(
-        'The `server.enhanceMiddleware` config option is deprecated and will be ' +
-          'removed in a later release. Please use `server.unstable_middleware` ' +
-          'or `server.unstable_priorityMiddleware` instead, and ' +
-          '`server.unstable_onServerCreated` to access the Metro server instance.',
-      );
-    }
     enhancedMiddleware = config.server.enhanceMiddleware(
       enhancedMiddleware,
       metroServer,

packages/metro/src/integration_tests/__tests__/server-extraMiddleware-test.js

@@ -155,24 +155,16 @@ describe('runServer custom middleware', () => {
     expect(events).toEqual([['config', true], ['runServer', true], 'ready']);
   });
 
-  test('does not warn for the default server.enhanceMiddleware', async () => {
+  test('applies server.enhanceMiddleware without warning', async () => {
     const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
-    await startServer(await loadConfig());
+    const enhanceMiddleware = jest.fn(middleware => middleware);
+    await startServer(await loadConfig({enhanceMiddleware}));
 
-    expect(warn).not.toHaveBeenCalled();
-    warn.mockRestore();
-  });
-
-  test('warns when server.enhanceMiddleware is set', async () => {
-    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
-    await startServer(
-      await loadConfig({enhanceMiddleware: middleware => middleware}),
-    );
-
-    expect(warn).toHaveBeenCalledWith(
-      expect.stringContaining('DEPRECATED'),
-      expect.stringContaining('`server.enhanceMiddleware`'),
+    expect(enhanceMiddleware).toHaveBeenCalledWith(
+      expect.any(Function),
+      expect.any(MetroServer),
     );
+    expect(warn).not.toHaveBeenCalled();
     expect((await request(BUNDLE_PATH)).status).toBe(200);
     warn.mockRestore();
   });