Init: Exclude mdx stories when docs feature isn't selected during init

[valentinpalkovic]

Closes #32138

What I did

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

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 pull request has been released as version 0.0.0-pr-32142-sha-424d5226. Try it out in a new sandbox by running npx [email protected] sandbox or in an existing project with npx [email protected] upgrade.

More information

Published version	0.0.0-pr-32142-sha-424d5226
Triggered by	@valentinpalkovic
Repository	storybookjs/storybook
Branch	valentin/init-storybook-without-mdx-stories
Commit	424d5226
Datetime	Mon Jul 28 12:58:55 UTC 2025 (1753707535)
Workflow run	16569685274

To request a new release of this pull request, mention the @storybookjs/core team.

core team members can create a new canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=32142

Greptile Summary

This PR fixes a bug where Storybook's initialization process was incorrectly including MDX story patterns in the main configuration even when users selected minimal installations without the docs feature. The change addresses issue #32138 by making the story configuration dynamic based on selected features during init.

The core fix involves three coordinated changes:

1. Type Safety Improvement: The GeneratorOptions.features field is changed from string[] to Array<GeneratorFeature> in types.ts, restricting valid feature values to 'docs', 'test', and 'onboarding'. This provides compile-time checking and prevents invalid feature strings.

2. Conditional MDX Pattern Logic: The configureMain function in configure.ts is modified to conditionally add MDX story patterns (**/*.mdx) to the stories array only when features.includes('docs') is true. Previously, MDX patterns were always included regardless of feature selection.

3. Feature Parameter Passing: The baseGenerator.ts file is updated to pass the features array to the configureMain function call, ensuring that feature selection made during initialization is properly communicated to the configuration generation.

This change integrates with Storybook's existing feature system, which allows users to selectively enable functionality like docs, testing, and onboarding during the initialization process. The fix prevents "No story files found" warnings when running minimal Storybook installations that don't need MDX support, while maintaining backward compatibility for full installations that include the docs addon.

Confidence score: 4/5

• This is a targeted bug fix that should resolve the specific issue without introducing new problems
• The implementation follows good practices with type safety improvements and conditional logic
• Need to verify that the feature detection logic works correctly across all initialization scenarios and that no edge cases are missed

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☁️ Nx Cloud last updated this comment at 2025-07-28 14:16:14 UTC

[storybook-pr-benchmarking]

Package Benchmarks

^{Commit: 2875061, ran on 28 July 2025 at 14:01:25 UTC}

The following packages have significant changes to their size or dependencies:

@storybook/builder-webpack5

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Dependency count	198	198	0
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Dependency size	31.32 MB	31.35 MB	🚨 +29 KB 🚨
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@storybook/ember

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Dependency count	203	203	0
Self size	28 KB	28 KB	0 B
Dependency size	28.05 MB	28.08 MB	🚨 +29 KB 🚨
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@storybook/nextjs

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Dependency count	538	538	0
Self size	903 KB	903 KB	0 B
Dependency size	59.05 MB	59.08 MB	🚨 +29 KB 🚨
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@storybook/react-webpack5

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Dependency count	286	286	0
Self size	25 KB	25 KB	0 B
Dependency size	43.64 MB	43.67 MB	🚨 +29 KB 🚨
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@storybook/server-webpack5

	Before	After	Difference
Dependency count	210	210	0
Self size	17 KB	17 KB	0 B
Dependency size	32.59 MB	32.62 MB	🚨 +29 KB 🚨
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@storybook/preset-react-webpack

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Dependency count	177	177	0
Self size	24 KB	24 KB	0 B
Dependency size	30.47 MB	30.50 MB	🚨 +29 KB 🚨
Bundle Size Analyzer	Link	Link