Warnings + error messages with hot reload + yarn v2

[brandon-leapyear]

Bug Report

Adding hot reload with yarn 2 in a new nest project runs the nest server successfully (i.e. curl localhost:3000 returns "Hello world"), but the output shows a deprecation warning and error messages related to requiring uninstalled packages.

Repro:

1. nest new
2. yarn set version berry && yarn
3. Add hot reload
   1. Follow instructions per https://docs.nestjs.com/recipes/hot-reload
   2. Replace start-server-webpack-plugin with run-script-webpack-plugin (Please upgrade to Webpack 5 ericclemmons/start-server-webpack-plugin#40 (comment))
   3. Fix WatchIgnorePlugin (docs(hot-reload): update hot-reload.md docs.nestjs.com#1568)
   4. Run yarn add -D webpack@5.9.0 (Move webpack to peerDependency for Yarn v2 + hot reload nest-cli#992)
4. yarn start:dev

Current behavior

You'll see one deprecation warning:

(node:35944) [DEP_WEBPACK_WATCH_WITHOUT_CALLBACK] DeprecationWarning: A 'callback' argument need to be provided to the 'webpack(options, callback)' function when the 'watch' option is set. There is no way to handle the 'watch' option without a callback.
(Use `node --trace-deprecation ...` to show where the warning was created)

and errors like

ERROR in ./.yarn/unplugged/@nestjs-core-virtual-330e9c6eb9/node_modules/@nestjs/core/nest-application.js 16:102-145
Module not found: Error: @nestjs/core tried to access @nestjs/websockets (a peer dependency) but it isn't provided by its ancestors; this makes the require call ambiguous and unsound.

Required package: @nestjs/websockets (via "@nestjs/websockets/socket-module")
Required by: @nestjs/core@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1 (via /Users/bchinn/Desktop/yarn2/nest-hrm-yarn2/.yarn/unplugged/@nestjs-core-virtual-330e9c6eb9/node_modules/@nestjs/core/)
Ancestor breaking the chain: @nestjs/platform-express@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1
Ancestor breaking the chain: @nestjs/testing@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1
Ancestor breaking the chain: foo@workspace:.


 @ ./.yarn/unplugged/@nestjs-core-virtual-330e9c6eb9/node_modules/@nestjs/core/index.js 25:21-50
 @ ./src/main.ts 3:15-38

Now #5477 correctly added these packages to peerDependencies and specified them as optional with peerDependenciesMeta, but I think the way NestJS tries to load optional dependencies (i.e. try-catch require) triggers an error message with Yarn v2.

nest/packages/core/nest-application.ts

Lines 34 to 38 in 8c503d3

	const {
	MicroservicesModule,
	} = optionalRequire('@nestjs/microservices/microservices-module', () =>
	require('@nestjs/microservices/microservices-module'),
	);

nest/packages/core/helpers/optional-require.ts

Lines 1 to 7 in 8c503d3

	export function optionalRequire(packageName: string, loaderFn?: Function) {
	try {
	return loaderFn ? loaderFn() : require(packageName);
	} catch (e) {
	return {};
	}
	}

Input Code

See repro above

Expected behavior

yarn start:dev should not show any deprecation warnings or error messages, the way it displays without the "Add hot reload" step in the repro.

Possible Solution

Some possible solutions:

1. Only require optional dependencies when they're actually used
2. Implement optionalRequire differently, possibly using the PnP API to check if a package is installed before trying to require it

Environment

Nest version: X.Y.Z

 
For Tooling issues:
- Node version: XX  
- Platform:  

Others:

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

But also, more generally speaking, I would expect

nest build --webpack --webpackPath webpack.config.js

with

module.exports = function(options) {
  return options
}

to be equivalent to nest build, but nest build finishes successfully, while it errors with a noop webpack.config.js

[Tony133]

Hi, @brandon-leapyear

Try doing this:

• nest n appor nest nest app

• Package manger uses yarn

• yarn set version berry && yarn If you want to use version 2 of yarn

• yarn add webpack-node-externals start-server-nestjs-webpack-plugin --dev

• Create file webpack-hmr.config.jsin the project root

I used this:

const webpack = require('webpack');
const nodeExternals = require('webpack-node-externals');
const StartServerPlugin = require('start-server-nestj-webpack-plugin');

module.exports = function(options) {
  return {
    ...options,
    entry: ['webpack/hot/poll?100', options.entry],
    externals: [
      nodeExternals({
        allowlist: ['webpack/hot/poll?100'],
      }),
    ],
    plugins: [
      ...options.plugins,
      new webpack.HotModuleReplacementPlugin(),
      new webpack.WatchIgnorePlugin({
          paths: [/\.js$/, /\.d\.ts$/]
      }),
      new StartServerPlugin({ name: options.output.filename }),
    ],
  };
};

• Open the package.json and edit the yarn run start:dev script in :
  "start:dev": "nest build --webpack --webpackPath webpack-hmr.config.js"

and then from the terminal do: yarn run start:dev

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

@Tony133 what would that do differently? I already included in my repro instructions the step of replacing start-server-webpack-plugin with run-script-webpack-plugin

[Tony133]

I tried as I wrote you above and it works if you want to try

at the most if you want to turn the test repository

[Tony133]

the problem if I'm not mistaken is at this point:

ii. Replace start-server-webpack-plugin with run-script-webpack-plugin

you should replace: start-server-webpack-plugin with start-server-nestjs-webpack-plugin and not with "run-script-webpack-plugin"

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

@Tony133 That's not the issue. run-script-webpack-plugin is basically the same as start-server-nestjs-webpack-plugin. Are you sure you tried it with Yarn 2? Yarn 2 does things differently.

So I actually got it working by replacing webpack-node-externals with webpack-pnp-externals. In summary, the following instructions get hot-reload to work with yarn 2 (modulo deprecation warnings):

1. yarn add -D webpack-pnp-externals run-script-webpack-plugin webpack@5.9.0 (completely replaces the existing npm install instruction in the docs)
2. Add the following webpack-hmr.config.js file:

   const webpack = require('webpack');
   const nodeExternals = require('webpack-node-externals');
   const { RunScriptWebpackPlugin } = require('run-script-webpack-plugin');
   const { WebpackPnpExternals } = require('webpack-pnp-externals');
   
   module.exports = function(options) {
     return {
       ...options,
       entry: ['webpack/hot/poll?100', options.entry],
       watch: true,
       externals: [
         WebpackPnpExternals({ exclude: ['webpack/hot/poll?100'] }),
       ],
       plugins: [
         ...options.plugins,
         new webpack.HotModuleReplacementPlugin(),
         new webpack.WatchIgnorePlugin({
           paths: [/\.js$/, /\.d\.ts$/]
         }),
         new RunScriptWebpackPlugin({ name: options.output.filename }),
       ],
     };
   };

   The differences with the webpack-hmr.config.js in the docs are:
   • Use RunScriptWebpackPlugin instead of StartServerWebpackPlugin (StartServerWebpackPlugin incompatible with Webpack 5)
   • Fix WatchIgnorePlugin to use paths key
   • Use WebpackPnpExternals instead of webpack-node-externals (yarn 2 does not have a node_modules directory)
3. Change start:dev script as usual

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

In total, to resolve this issue, I'd recommend adding the above instructions to the NestJS docs about Hot Reload for Yarn v2, as well as fixing the DEP_WEBPACK_WATCH_WITHOUT_CALLBACK deprecation message (i believe this happens even without Yarn v2)

[Tony133]

For this point:
"Use RunScriptWebpackPlugin instead of StartServerWebpackPlugin (StartServerWebpackPlugin incompatible with Webpack 5"
I install: start-server-nestjs-webpack-plugin

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

@Tony133 I understand. Again, that's not the issue here. I personally prefer run-script-webpack-plugin, but either works. I do recommend NestJS docs say run-script-webpack-plugin, to avoid having special dependencies that are special to NestJS

[Tony133]

Ok, I do some tests then I'll let you know

[Tony133]

@brandon-leapyear For this warning:

(node:35944) [DEP_WEBPACK_WATCH_WITHOUT_CALLBACK] DeprecationWarning: A 'callback' argument need to be provided to the 'webpack(options, callback)' function when the 'watch' option is set. There is no way to handle the 'watch' option without a callback.
(Use `node --trace-deprecation ...` to show where the warning was created)

Just remove:

watch: true

reference: --> webpack/webpack-cli#1918

[Tony133]

The documentation must also be updated for the yarn I did a shot as you have seen and proposed to specify it better in the documentation.

I could also use that pull to update the documentation

I add here the reference to the pull to connect the speech: ---> nestjs/docs.nestjs.com#1568

[brandon-leapyear]

✨ This is an old work account. Please reference @brandonchinn178 for all future communication ✨

---

Just remove watch: true

But... I want watch: true for hot reload

[Tony133]

instead for this mistake:

ERROR in ./.yarn/unplugged/@nestjs-core-virtual-330e9c6eb9/node_modules/@nestjs/core/nest-application.js 16:102-145
Module not found: Error: @nestjs/core tried to access @nestjs/websockets (a peer dependency) but it isn't provided by its ancestors; this makes the require call ambiguous and unsound.

Required package: @nestjs/websockets (via "@nestjs/websockets/socket-module")
Required by: @nestjs/core@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1 (via /Users/bchinn/Desktop/yarn2/nest-hrm-yarn2/.yarn/unplugged/@nestjs-core-virtual-330e9c6eb9/node_modules/@nestjs/core/)
Ancestor breaking the chain: @nestjs/platform-express@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1
Ancestor breaking the chain: @nestjs/testing@virtual:6847a7e26c6f65e9a07a05ac6fd51a817f487ca65a3f4eb6074a6e87e9e5a9b8d604589ccca3616c3ade1ca80766e0dab48ed3499f9be6e35afa8028ddc2857f#npm:7.6.1
Ancestor breaking the chain: foo@workspace:.

to me it doesn't