No external modules needed - caused due to ES6 module imports with webpack 5.4.0

[dpkshrma]

Bug Report

Description

• What went wrong?

Node modules are not auto-packing as expected. Please check the following repository which helps reproduce this issue - https://github.com/dpkshrma/sls-webpack-peer-dep-issue

According to the documentation, the below configuration should allow to selectively pack only the imported modules:

// webpack.config.js
var nodeExternals = require('webpack-node-externals')

module.exports = {
  // we use webpack-node-externals to excludes all node deps.
  // You can manually set the externals too.
  externals: [nodeExternals()],
}

# serverless.yml
custom:
  webpack:
    includeModules: true # enable auto-packing of external modules

But, with the peer dependency webpack": "^5.4.0, no npm modules are packaged in the artifacts:

With peer dependency webpack": "^4.5.1, it works as expected:

• What did you expect should have happened?
  Node modules should have been auto-packed with webpack version 5.4.0

• What was the config you used?

service: sls-webpack-peer-dep-issue

provider:
  name: aws
  versionFunctions: false
  runtime: nodejs12.x
  region: ap-south-1
  apiGateway:
    shouldStartNameWithService: true

plugins:
  - serverless-webpack

custom:
  webpack:
    webpackConfig: webpack.config.js
    includeModules: true
    packager: "yarn"

functions:
  app:
    handler: index.default
    events:
      - http: ANY /{any+}

• What stacktrace or error message from your provider did you see?

$ sls package
Serverless: Bundling with Webpack...
asset index.js 838 bytes [emitted] [minimized] (name: index)
runtime modules 931 bytes 4 modules
orphan modules 126 bytes [orphan] 3 modules
./index.js + 3 modules 387 bytes [not cacheable] [built] [code generated]
webpack compiled successfully in 1108 ms
Serverless: No external modules needed
(node:15690) [DEP_WEBPACK_CHUNK_MODULES_ITERABLE] DeprecationWarning: Chunk.modulesIterable: Use new ChunkGraph API
(Use `node --trace-deprecation ...` to show where the warning was created)
Serverless: Packaging service...
✨  Done in 9.06s.

Similar or dependent issue(s):

• No external modules needed #483

Additional Data

• Serverless-Webpack Version you're using: 5.3.5
• Webpack version you're using: 5.4.0
• Serverless Framework Version you're using: 2.10.0
• Operating System: MacOS
• Stack Trace (if available):

[j0k3r]

Duplicates #651