feat: run as a plugin from the top-level plugins of a multi-configuration by alexander-akait · Pull Request #5765 · webpack/webpack-dev-server

alexander-akait · 2026-10-15T15:18:13Z

Summary

webpack/webpack#22702 lets a multi-configuration list plugins next to parallelism; webpack applies them once to the MultiCompiler. With the dev server there, one server serves every configuration:

module.exports = Object.assign([appConfig, workerConfig], {
  plugins: [new WebpackDevServer({ port: 8080 })],
});

apply() already handled a MultiCompiler, so this needs no new code path. It now taps MultiCompiler.hooks.shutdown where webpack has it (5.110.0+) and keeps looping over the child compilers on older webpack. The peer range stays ^5.101.0 and webpack is not bumped; the fallback carries a TODO to remove it in the next major.

webpack 5.112.0 ships #22702, and the lockfile is updated to it, so CI runs the top-level plugins test instead of skipping it. MultiCompiler plugin tests:

webpack	pass	skipped
5.111.1	5	1 (top-level `plugins` unsupported)
5.112.0 (lockfile)	6	0

The branch is merged with main, including #5750 (dev-middleware 8.4.0 client).

The webpack-cli side (keeping these options under --config-name and extends) is webpack/webpack-cli#4871.

What kind of change does this PR introduce?

feat

Did you add tests for your changes?

Yes, in test/e2e/api-plugin.test.js:

serving both configurations from the top-level plugins, with setup, listen and stop each called once. It is skipped on webpack older than 5.112.0 (feature-detected, with a TODO to drop the check in the next major).
stopping once on a MultiCompiler without hooks.shutdown, covering the fallback for webpack older than 5.110.0.

Does this PR introduce a breaking change?

No.

If relevant, what needs to be documented once your changes are merged or what have you already documented?

Added "Multiple configurations" to examples/api/plugin/README.md. The webpack.js.org dev-server page could mention it now that webpack 5.112.0 supports top-level plugins.

Use of AI

Written with Claude Code: it made the change and the tests, and ran them against both the released webpack and webpack with #22702, directed and reviewed by the author.

🤖 Generated with Claude Code

https://claude.ai/code/session_01ML8tLtqrJohECUzhdBwqsw

Generated by Claude Code

Summary by CodeRabbit

New Features
- A single development server can serve assets from every configuration in a multi-configuration setup when the installed webpack version supports top-level plugins.
Bug Fixes
- Improved server shutdown handling for multi-configuration setups, including cases where the combined compiler does not provide a shutdown hook. The server now stops only once.
Documentation
- Added an example showing how to configure the development server for multiple configurations, including the webpack version requirement for top-level plugins.

Generated by Claude Code

…tion

changeset-bot · 2026-10-15T15:18:19Z

🦋 Changeset detected

Latest commit: 662404d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
webpack-dev-server	Minor

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coderabbitai · 2026-10-15T15:21:53Z

No actionable comments were generated in the recent review. 🎉

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examples/api/plugin/README.md

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Walkthrough

Server.apply now registers shutdown on the compiler when its shutdown hook is available. Otherwise, it registers on child compilers. Documentation and tests cover using a top-level Server plugin to serve multiple configurations, including older webpack versions without the MultiCompiler shutdown hook.

Priority: ⬇️ Low

Merge Risk: ⚪ Minimal · up to 66240

The documented setup lets one server serve multiple configurations, with shutdown paths designed to stop it once. No material merge risk is established.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly describes the main change: enabling webpack-dev-server to run from the top-level plugins list in a multi-configuration setup.
Docstring Coverage		No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2 files. (1 skipped: 1 unsupported.)

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codecov · 2026-10-15T16:20:34Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.16%. Comparing base (dc9a72c) to head (662404d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5765   +/-   ##
=======================================
  Coverage   95.15%   95.16%           
=======================================
  Files           6        6           
  Lines        4976     4982    +6     
=======================================
+ Hits         4735     4741    +6     
  Misses        241      241

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…lugin-mode

5.112.0 applies a multi-configuration's top-level `plugins` to the MultiCompiler (webpack/webpack#22702), so the test serving both configurations from there runs instead of being skipped. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UjuMAuk9o6UazjHzcAQCTA

socket-security · 2026-10-17T14:13:38Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	webpack@5.111.1 ⏵ 5.112.0	^-12			^-1

View full report

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UjuMAuk9o6UazjHzcAQCTA

feat: run as a plugin from the top-level plugins of a multi-configura…

27453ab

…tion

alexander-akait and others added 2 commits October 17, 2026 14:11

Merge remote-tracking branch 'origin/main' into feat/multi-compiler-p…

439a53e

…lugin-mode

docs: name the webpack version that supports top-level plugins

662404d

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UjuMAuk9o6UazjHzcAQCTA

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feat: run as a plugin from the top-level plugins of a multi-configuration - #5765

feat: run as a plugin from the top-level plugins of a multi-configuration#5765
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