Addon-Vitest: Support Vitest canaries

[valentinpalkovic]

Closes #33832

What I did

When adding @storybook/addon-vitest to a project that uses a canary version of Vitest, the initialization/postinstall process failed. Now, Vitest canaries are supported during init.

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

• New Features
  • Vitest prerelease versions (such as 3.0.0-beta.1) are now fully supported, allowing development teams to test with beta builds without compatibility issues.
  • Vitest canary versions are now recognized as compatible, enabling seamless integration with the latest experimental development builds.

[github-actions]

	Fails
🚫	The "#### Manual testing" section must be filled in. Please describe how to test the changes you've made, step by step, so that reviewers can confirm your PR works as intended.

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View your CI Pipeline Execution ↗ for commit b6d6bf1

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☁️ Nx Cloud last updated this comment at 2026-02-12 10:57:48 UTC

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes add support for Vitest canary and prerelease versions by introducing a canary version detection mechanism (checking if version starts with 0.0.0) in the validation logic, along with corresponding test cases to verify these versions are treated as compatible.

Changes

Cohort / File(s)	Summary
Vitest Canary Version Support code/core/src/cli/AddonVitestService.ts, code/core/src/cli/AddonVitestService.test.ts	Added canary version bypass using isCanary computed property that checks for 0.0.0 prefix; introduced two new test cases validating prerelease and canary versions are considered compatible when MSW is not installed.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

✨ Finishing touches

• 📝 Generate docstrings

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No actionable comments were generated in the recent review. 🎉

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