Storybook <Stories /> doc block in mdx no longer rendering after upgrading to version 8.1.0

[ryanelian]

Summary

I have stories written like this:

RouterProvider.mdx

import { Canvas, Meta } from '@storybook/blocks';

import { Title, Subtitle, Description, Primary, Controls, Stories, Source } from '@storybook/blocks';

import RouterProviderStories from './RouterProvider.stories';

<Meta of={RouterProviderStories} />

<Title />

<Subtitle />

Redacted

<Stories />

RouterProvider.stories.tsx

import type { Meta } from '@storybook/react';

import { RouterProvider } from 'react-aria-components';

// More on how to set up stories at: https://storybook.js.org/docs/writing-stories#default-export
const meta = {
  title: 'Components/RouterProvider',
  component: RouterProvider,
  parameters: {
    // Optional parameter to center the component in the Canvas. More info: https://storybook.js.org/docs/configure/story-layout
    layout: 'centered',
  },
} satisfies Meta<typeof RouterProvider>;

export default meta;

export { RouterProviderStory } from './RouterProvider.story';

Where that story re-exported from another file is a way for us to customize the rendering of the component and display source code appropriate for our use case:

import component from './RouterProvider.story.source';
import sourceCode from './RouterProvider.story.source?raw';

export const RouterProviderStory = {
  name: 'RouterProvider',
  render: component,
  parameters: {
    layout: 'centered',
    storySource: {
      source: sourceCode,
    },
    design: [
      {
        type: 'link',
        url: 'https://react-spectrum.adobe.com/react-aria/routing.html',
      },
    ],
    docs: {
      source: {
        code: sourceCode,
      },
    },
  },
};

The component being rendered and the source code of the component is not relevant for this discussion, and therefore not included to not distract the focus from the core issue.

When updating to version 8.1.0, these MDX <Stories /> block failed to render.

Additional information

For some reason, stories generated by autodocs tags: ['autodocs'], gets story blocks generated correctly.

But stories that are hand-written using MDX do not.

Create a reproduction

No response

[shilman]

Aha, sorry about that. It's an unintentional breaking change due to #26634

I'll chat with the team and figure out a workaround. Following up in #27143