[alexander-akait]

Follow-up to #4847 and #4885. Fixes #2408 for webpack-dev-server 6.

Shared devServer options

Multi-configurations often share one devServer object between configurations. The automatic port of the first dev server was written to that shared object, so every other dev server got the same port and failed with EADDRINUSE. The CLI now copies the options for each configuration.

Test for multiple dev servers without ports

The test for #2408 ("should work in multi compiler mode with multiple dev servers") was skipped. It now runs with webpack-dev-server 6:

• configurations without ports share one devServer object;
• each dev server must get a distinct port;
• every dev server must serve the bundles of all compilers.

Its config imported the shared options with const { devServerConfig } = require(...), but the helper exports the object itself, so devServer was undefined. Other configs import it the same way; they are left unchanged to keep their snapshots.

The test fails without the fix and passes with it.

Free ports in the new serve tests

The serve tests added in #4847 (automatic-ports, error-handling, per-compiler, rebuild) now use getFreePort from #4885. Before, they took ports from the ephemeral range, where other connections can take them before the dev server listens. getFreePort accepts ports to exclude, as the per-compiler test needs two.

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Generated by Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Development servers using shared configuration now receive distinct ports, allowing multiple servers to run without explicit port assignments.
• Tests
  • Added coverage for serving multiple compilers on separate ports. Multi-server coverage is skipped for webpack-dev-server 5.

[changeset-bot]

🦋 Changeset detected

Latest commit: c0cf560

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

This PR includes changesets to release 1 package

Name	Type
webpack-cli	Patch

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[github-actions]

This PR is packaged and the instant preview is available (d4ee8bd).

Install it locally:

• npm

npm i -D create-webpack-app@https://pkg.pr.new/create-webpack-app@d4ee8bd webpack-cli@https://pkg.pr.new/webpack-cli@d4ee8bd

• yarn

yarn add -D create-webpack-app@https://pkg.pr.new/create-webpack-app@d4ee8bd webpack-cli@https://pkg.pr.new/webpack-cli@d4ee8bd

• pnpm

pnpm add -D create-webpack-app@https://pkg.pr.new/create-webpack-app@d4ee8bd webpack-cli@https://pkg.pr.new/webpack-cli@d4ee8bd

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.08%. Comparing base (9bcb6d5) to head (c0cf560).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4886   +/-   ##
=======================================
  Coverage   95.07%   95.08%           
=======================================
  Files          14       14           
  Lines        5873     5874    +1     
  Branches      895      894    -1     
=======================================
+ Hits         5584     5585    +1     
  Misses        288      288           
  Partials        1        1           

Files with missing lines	Coverage Δ
packages/webpack-cli/src/webpack-cli.ts	96.95% <100.00%> (+<0.01%)	⬆️

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[coderabbitai]

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Commits

Reviewing files that changed from the base of the PR and between 9bcb6d5 and c0cf560.

Files selected for processing: 9

• .changeset/shared-dev-server-options.md
• packages/webpack-cli/src/webpack-cli.ts
• test/serve/automatic-ports/automatic-ports.test.js
• test/serve/basic/multi-dev-server.config.js
• test/serve/basic/serve-basic.test.js
• test/serve/error-handling/serve-error-handling.test.js
• test/serve/per-compiler/serve-per-compiler.test.js
• test/serve/rebuild/serve-rebuild.test.js
• test/utils/test-utils.js

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Walkthrough

The CLI now shallow-copies supplied devServer options. The multi-server test configuration no longer sets separate ports. The updated test checks that two servers receive distinct ports and return successful responses for both compiler outputs. The shared getFreePort test utility now accepts excluded ports, and several serve tests use it instead of dynamically importing get-port.

Priority: Normal

Severity of issue fixed: Medium

Merge Risk: Minimal · up to c0cf5

No merge-blocking risk was identified.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Linked Issues check		Issue #2408 requires webpack serve to serve multiple configurations with unique publicPath values from the same port. The PR instead copies each shared devServer options object and tests that th…	Implement the #2408 behavior for unique publicPath values: run the configurations from one shared server and add an automated test that verifies one port serves all required bundle paths. If distinct ports are the intended replacement, up…

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main fix: assigning distinct ports to development servers that share devServer options.
Out of Scope Changes check		The changed files stay within the multi-server serve scope of #2408. The CLI copy prevents shared options from reusing an automatic port. The basic serve test covers the multi-server case. The `getFre…
Docstring Coverage		No eligible functions found in the changed files. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…

Full details: Out of Scope Changes check

Explanation

The changed files stay within the multi-server serve scope of #2408. The CLI copy prevents shared options from reusing an automatic port. The basic serve test covers the multi-server case. The getFreePort updates stabilize the related serve tests, and the changeset documents the fix.

Full details: Docstring Coverage

Explanation

No eligible functions found in the changed files. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 0 functions across 8 files. (1 skipped: 1 unsupported.)

Full details: Linked Issues check

Explanation

Issue #2408 requires webpack serve to serve multiple configurations with unique publicPath values from the same port. The PR instead copies each shared devServer options object and tests that the servers receive two distinct ports (test/serve/basic/serve-basic.test.js). The PR does not implement or verify the same-port behavior required by #2408.

Resolution

Implement the #2408 behavior for unique publicPath values: run the configurations from one shared server and add an automated test that verifies one port serves all required bundle paths. If distinct ports are the intended replacement, update the linked issue requirements before relying on this PR as its fix.

Finishing Touches

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