Initial vendor chunks not respecting minSize

Bug report

What is the current behavior?

Changing minSIze to 520KB generates synchronous ( initial ) vendor chunk of size 517KB.

If the current behavior is a bug, please provide the steps to reproduce.

I have two entry points with async/sync modules.

// a.js
import { run } from "./app/app";
import ("lodash");
import "bootstrap";
import "./main.scss";
import { AlertService } from "./app/alert.service";
import { ComponentService } from "./app/component.service";
const alertService = new AlertService();
const componentService = new ComponentService();
run(alertService, componentService);

// b.js
import { run } from "./app/app";
import ("lodash");
import ("bootstrap");
import "./main.scss";
import { AlertService } from "./app/alert.service";
import { ComponentService } from "./app/component.service";
const alertService = new AlertService();
const componentService = new ComponentService();
run(alertService, componentService);

The optimization plugin config without custom minSize is as follows where everything generated as expected

  optimization: {
    minimize: false,
    splitChunks: {
      chunks: "initial",
      // minSize: 520000,
    }
  }

generated chunks with above config

4.0430a28c67c95515623d.bundle.js   509 KiB       4  [emitted] [immutable]  [big]  
5.177897857c70dc7eaa96.bundle.js   531 KiB    5, 6  [emitted] [immutable]  [big]  
6.507730afe61b6ceecf70.bundle.js   531 KiB       6  [emitted] [immutable]  [big]  
a.ac0e9c622ffd0aace615.bundle.js  10.2 KiB       1  [emitted] [immutable]         a
a~b.1fafc50267cf2e753b51.bundle.js   148 KiB       0  [emitted] [immutable]         a~b
b.b9218b218e06859b7b0d.bundle.js  18.5 KiB       2  [emitted] [immutable]         b
imgs/webpack.523e1b932381f19b26060571ccfc7a31.svg  2.29 KiB          [emitted] [immutable]         
index.html  1.77 KiB          [emitted]                     
vendors~a.50adedf6af3fbeb56ed3.bundle.js   517 KiB    3, 4  [emitted] [immutable]  [big]  vendors~a

If uncommented minSize from above config following is the generated output

3.4fe397947d6a74a38870.bundle.js   509 KiB       3  [emitted] [immutable]  [big]  
4.5289e4657b1f86d851f1.bundle.js   531 KiB    4, 5  [emitted] [immutable]  [big]  
5.ad452c25e6aa46a1cdff.bundle.js   531 KiB       5  [emitted] [immutable]  [big]  
a.974925a2f0898c477b9e.bundle.js   158 KiB       0  [emitted] [immutable]         a
b.2cd9e2bdb8245dd78851.bundle.js   165 KiB       1  [emitted] [immutable]         b
imgs/webpack.523e1b932381f19b26060571ccfc7a31.svg  2.29 KiB          [emitted] [immutable]         
index.html  1.72 KiB          [emitted]                     
vendors~a.e51176a01049374bf6f1.bundle.js   517 KiB    2, 3  [emitted] [immutable]  [big]  vendors~a

Note that a.bundle.js and b.bundle.js is increased as main.scss is not spitted out to separate chunk due to minSIze restriction. But its still creating vendor~a chunk even tho its size is 517kb.

If we set minSize to significantly increased number i.e 999999999 we get the expected output with no initial chunks

2.4d4ab8a0eebe11a6149c.bundle.js   509 KiB       2  [emitted] [immutable]  [big]  
3.434ee8f39d57e8f7dee7.bundle.js   531 KiB    3, 4  [emitted] [immutable]  [big]  
4.d890b35757aa13206d0e.bundle.js   531 KiB       4  [emitted] [immutable]  [big]  
a.16d5f9d877a088513a7d.bundle.js   674 KiB    0, 2  [emitted] [immutable]  [big]  a
b.062bc745c5f2e5e55948.bundle.js   165 KiB       1  [emitted] [immutable]         b
imgs/webpack.523e1b932381f19b26060571ccfc7a31.svg  2.29 KiB          [emitted] [immutable]         
index.html  1.66 KiB          [emitted]           

What is the expected behavior? When setting minSize to 520kb vendor~a chunk should not be generated as happening with main.scss, respecting minSize.

Other relevant information: webpack version: 4.44.2 Node.js version: 12.19.0 Operating System: ubuntu budgie Additional tools:

[sokra]

Thanks. I found the problem. It’s a bug in webpack.

[sokra]

Probably today