[Bug]: Found a 'github-flavored-markdown-mdx' migration even without mdx files in the project

[Stunext]

Describe the bug

There seems to be a bug where updating or running:

npx storybook@next automigrate

Always offers the migration to github-flavored-markdown-mdx even when there are no mdx or jsx files in the project; I'm talking about an EMPTY project. Storybook 7 is supposed to use MDX2 and no longer supports GFM and that you recommend installing it as a development dependency if you use its features. I wonder what features? How can I use MDX2 without GFM which should I avoid using? If it is assumed that the package isn't provided by default during migration, then the storybook can be used without it.

To Reproduce

New vite project

npm create vite@latest

Select react project.

npx storybook@latest init

This command does not trigger 'github-flavored-markdown-mdx' migration

Then:

npx storybook@next automigrate or npx storybook@latest upgrade

Found a 'github-flavored-markdown-mdx' migration, even if you delete all files in the project. How is this detected?

System

Environment Info:

  System:
    OS: Linux 5.15 Ubuntu 22.04.2 LTS 22.04.2 LTS (Jammy Jellyfish)
    CPU: (12) x64 AMD Ryzen 5 5600X 6-Core Processor
  Binaries:
    Node: 19.8.1 - ~/.nvm/versions/node/v19.8.1/bin/node
    npm: 9.5.1 - ~/.nvm/versions/node/v19.8.1/bin/npm
  Browsers:
    Chrome: 110.0.5481.177
  npmPackages:
    @storybook/addon-essentials: ^7.0.6 => 7.0.6 
    @storybook/addon-interactions: ^7.0.6 => 7.0.6 
    @storybook/addon-links: ^7.0.6 => 7.0.6 
    @storybook/blocks: ^7.0.6 => 7.0.6 
    @storybook/react: ^7.0.6 => 7.0.6 
    @storybook/react-vite: ^7.0.6 => 7.0.6 
    @storybook/testing-library: ^0.0.14-next.2 => 0.0.14-next.2

Additional context

No response

[shilman]

Looking at the code it's clear that this automigration always runs. @ndelangen @yannbf was this intentional? Do we want to gate it on the presence of MDX files in the project?

[L3au]

+1 Same confusion here

[Stunext]

This hint should only be displayed if you are using something from GFM and therefore should give compile errors. It is currently not understood what features you should not use to avoid GFM migration. The message also appears when you have several components created and with their MDX files; and the project works perfectly, therefore it is not clear why it is necessary if there is no problem.

[ndelangen]

The message also appears when you have several components created and with their MDX files

That's correct, we made that choice, because we figured we'd play things defensively.. better to warn when there's nothing wrong than to not warn, and have users be frustrated and spend a lot of time figuring out that's wrong.

How would we determine if a user is or is not using GFM?

We CAN detect if MDX is used, and if not, skip the warning (that's what my PR here does: #22186 it just need to be reviewed, merged and released.

[shilman]

Great Caesar's ghost!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.1.0-alpha.12 containing PR #22186 that references this issue. Upgrade today to the @future NPM tag to try it out!

npx sb@next upgrade --tag future

[shilman]

Jiminy cricket!! I just released https://github.com/storybookjs/storybook/releases/tag/v7.0.8 containing PR #22186 that references this issue. Upgrade today to the @latest NPM tag to try it out!

npx sb@latest upgrade