Next.js-Vite: Fix failing postcss mutation

[valentinpalkovic]

Closes #

What I did

Fixed an issue where some vite config options, such as root, were not defined inline, but provided via plugins, which led to a late resolution, and other plugins, like the nextjs-vite ones, were not able to read config.root in time.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

Caution

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

Summary by CodeRabbit

• Chores
  • Optimized internal build configuration management for improved maintainability.

[github-actions]

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☁️ Nx Cloud last updated this comment at 2026-02-20 10:09:15 UTC

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📝 Walkthrough

Walkthrough

Configuration settings (root, base, cacheDir) are centralized in the common Vite InlineConfig (sbConfig) instead of being returned from a builder-vite specific plugin. The projectRoot variable is no longer needed, and the plugin configuration is simplified.

Changes

Cohort / File(s)	Summary
Vite Configuration Refactoring code/builders/builder-vite/src/vite-config.ts	Moved root, base, and cacheDir configuration from a plugin-specific block to the top-level sbConfig in common configuration, eliminating the projectRoot variable and consolidating configuration logic.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

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