Addon Vitest: Fix dynamic import failure with Vitest 3

[Sidnioulz]

What I did

Fixes recent CI failures on ci:daily where dynamic imports of Vitest Browser failed with Vitest 3 due to how the addon code is transformed. We now directly import the right dependency from the get go.

Checklist for Contributors

Testing

ø

Manual testing

• Check if ci:daily now passes

Documentation

ø

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 integration now provides the current Vitest version to the test environment for better compatibility.
  • Setup now selects appropriate browser command modules based on Vitest version.

• Bug Fixes

  • Improved error handling and fallbacks for browser-mode test operations across Vitest versions.

• Chores

  • Test workspace dev server filesystem permissions expanded to allow needed test access.

[Copilot]

Pull request overview

This PR addresses Vitest 3 compatibility issues in @storybook/addon-vitest by avoiding a failing dynamic import path for browser commands and instead selecting the correct import target based on the Vitest version injected into the test context.

Changes:

• Add a new provided-context key to carry the running Vitest version through to the setup file.
• Provide context.vitest.version from the Vitest plugin (configureVitest) for consumption via inject().
• Update the Vitest setup file to choose @vitest/browser/context for Vitest 3 vs vitest/browser otherwise.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 2 comments.

File	Description
code/addons/vitest/src/vitest-provided-context.d.ts	Extends Vitest ProvidedContext typing with a new key for the Vitest version.
code/addons/vitest/src/vitest-plugin/setup-file.ts	Switches browser command import path based on injected Vitest version.
code/addons/vitest/src/vitest-plugin/index.ts	Provides Vitest version into the project context during configureVitest.
code/addons/vitest/src/constants.ts	Introduces the new provide-key constant for the Vitest version.

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📝 Walkthrough

Walkthrough

This PR adds a dependency-injection key for Vitest's runtime version, registers that version on the project during plugin configuration, and uses the injected version in the setup-file to conditionally import the correct browser command module (supporting both Vitest 3 and pre-3 layouts). It also refactors setup-files array construction and updates test workspace configuration.

Changes

Vitest version provision for runtime compatibility

Layer / File(s)	Summary
Define version provide key and type augmentation code/addons/vitest/src/constants.ts, code/addons/vitest/src/vitest-provided-context.d.ts	Introduce STORYBOOK_CORE_VITEST_VERSION_PROVIDE_KEY constant and extend Vitest's ProvidedContext interface to include the version string entry with proper type augmentation.
Refactor setup files array construction code/addons/vitest/src/vitest-plugin/index.ts	Change internalSetupFiles from resolved filesystem paths via fileURLToPath(import.meta.resolve(...)) to direct module specifiers array filtering.
Register version in plugin configuration code/addons/vitest/src/vitest-plugin/index.ts	Import the provide key and register context.vitest.version on the project via context.project.provide(...) during configureVitest.
Consume injected version in setup-file code/addons/vitest/src/vitest-plugin/setup-file.ts	Add imports for inject and the version key, introduce dynamic import helpers for browser modules, refactor resetMousePositionBeforeTests to read the injected version and choose between @vitest/browser/context (Vitest 3) or vitest/browser (pre-3), and refine error handling to ignore version-specific module-not-found errors while rethrowing unexpected failures.

Test workspace and debug updates

Layer / File(s)	Summary
Workspace filesystem access and debug logging test-storybooks/portable-stories-kitchen-sink/react-vitest-3/vitest.workspace.ts, code/addons/vitest/src/vitest-plugin/setup-file.ts	Add server.fs.allow: ["../../../"] to workspace Vite configuration and include a debug console.log('Frogs are often green.') statement in setup-file.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• storybookjs/storybook#34765: Both modify setup-file.ts to change how resetMousePositionBeforeTests imports and uses Vitest browser command modules.
• storybookjs/storybook#33086: Both adjust Vitest 3→4 browser interop by switching or conditionally loading @vitest/browser/context vs vitest/browser.

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[storybook-app-bot]

Package Benchmarks

^{Commit: 919585e, ran on 28 May 2026 at 13:56:26 UTC}

No significant changes detected, all good. 👏

[coderabbitai]

🧹 Nitpick comments (1)

code/addons/vitest/src/vitest-plugin/index.ts (1)

328-332: ⚡ Quick win

Avoid filter(Boolean) as string[] and encode the invariant in types.

Line 332 relies on a type assertion after runtime filtering, which weakens static guarantees. Build the array with conditional spread so the type is string[] without as.

♻️ Proposed refactor

-      const internalSetupFiles = [
-        '`@storybook/addon-vitest/internal/setup-file`',
-        areProjectAnnotationRequired &&
-          '`@storybook/addon-vitest/internal/setup-file-with-project-annotations`',
-      ].filter(Boolean) as string[];
+      const internalSetupFiles: string[] = [
+        '`@storybook/addon-vitest/internal/setup-file`',
+        ...(areProjectAnnotationRequired
+          ? ['`@storybook/addon-vitest/internal/setup-file-with-project-annotations`']
+          : []),
+      ];

As per coding guidelines, "Encode assumptions with static checks first; if an assumption is expected to always hold, prefer making it impossible via TypeScript types and existing lint rules".

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@code/addons/vitest/src/vitest-plugin/index.ts` around lines 328 - 332, The
current construction of internalSetupFiles uses runtime filter(Boolean) and a
type assertion, weakening type safety; instead build the array with a
conditional spread so it is statically a string[] (e.g., include
'`@storybook/addon-vitest/internal/setup-file`' and then
...(areProjectAnnotationRequired ?
['`@storybook/addon-vitest/internal/setup-file-with-project-annotations`'] : [])
), remove the filter(Boolean) and the "as string[]" assertion so the type of
internalSetupFiles is inferred as string[]; update any references expecting
string[] accordingly.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@code/addons/vitest/src/vitest-plugin/index.ts`:
- Around line 328-332: The current construction of internalSetupFiles uses
runtime filter(Boolean) and a type assertion, weakening type safety; instead
build the array with a conditional spread so it is statically a string[] (e.g.,
include '`@storybook/addon-vitest/internal/setup-file`' and then
...(areProjectAnnotationRequired ?
['`@storybook/addon-vitest/internal/setup-file-with-project-annotations`'] : [])
), remove the filter(Boolean) and the "as string[]" assertion so the type of
internalSetupFiles is inferred as string[]; update any references expecting
string[] accordingly.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: a2c4939c-4273-4c8d-bbc1-d5fd8c5dfaa8

📥 Commits

Reviewing files that changed from the base of the PR and between 3e9d7f8 and df63788.

📒 Files selected for processing (3)

• code/addons/vitest/src/vitest-plugin/index.ts
• code/addons/vitest/src/vitest-plugin/setup-file.ts
• test-storybooks/portable-stories-kitchen-sink/react-vitest-3/vitest.workspace.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• code/addons/vitest/src/vitest-plugin/setup-file.ts