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fix(stories): Fix HMR for .stories.tsx and .mdx files in Scraps #109630

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fix(stories): Fix HMR for .stories.tsx and .mdx files in Scraps #109630

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e1261f5
fix(stories): Fix HMR for .stories.tsx and .mdx files in Scraps
scttcper Feb 28, 2026
53a9ef7
fix(stories): Remove unused export from makeStorybookDocumentTitle
scttcper Feb 28, 2026
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6 changes: 3 additions & 3 deletions static/app/stories/apiReference.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ import {Tooltip} from '@sentry/scraps/tooltip';

import {IconChevron} from 'sentry/icons';
import {IconSearch} from 'sentry/icons/iconSearch';
import * as Storybook from 'sentry/stories';
import {Section} from 'sentry/stories/layout';
import {fzf} from 'sentry/utils/search/fzf';

interface APIReferenceProps {
Expand All @@ -21,7 +21,7 @@ export function APIReference(props: APIReferenceProps) {
const nodes = usePropTree(props.componentProps?.props ?? {}, query);

return (
<Storybook.Section>
<Section>
{props.componentProps?.description && <p>{props.componentProps.description}</p>}
<Container marginBottom="md">
<InputGroup>
Expand Down Expand Up @@ -87,7 +87,7 @@ export function APIReference(props: APIReferenceProps) {
</tbody>
</StoryTypesTable>
</StoryTableContainer>
</Storybook.Section>
</Section>
);
}

Expand Down
16 changes: 10 additions & 6 deletions static/app/stories/storybook.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -4,10 +4,14 @@ import {Children, Fragment, useEffect} from 'react';
import {Container} from '@sentry/scraps/layout';
import {Heading} from '@sentry/scraps/text';

import {makeStorybookDocumentTitle} from 'sentry/stories/view/storyExports';
import {StoryHeading} from 'sentry/stories/view/storyHeading';

import * as Storybook from './';
import {APIReference} from './apiReference';
import {Section, SideBySide} from './layout';

function makeStorybookDocumentTitle(title: string | undefined): string {
return title ? `${title} — Scraps` : 'Scraps';
}

type StoryRenderFunction = () => ReactNode | ReactNode[];
type StoryContext = (storyName: string, story: StoryRenderFunction) => void;
Expand Down Expand Up @@ -47,7 +51,7 @@ export function story(title: string, setup: SetupFunction): StoryRenderFunction
<Story key={name + idx} name={name} render={render} />
))}
{APIDocumentation.map((documentation, i) => (
<Storybook.APIReference key={i} componentProps={documentation} />
<APIReference key={i} componentProps={documentation} />
))}
</Fragment>
);
Expand All @@ -59,13 +63,13 @@ function Story(props: {name: string; render: StoryRenderFunction}) {
const isOneChild = Children.count(children) === 1;

return (
<Storybook.Section>
<Section>
<Container borderBottom="primary">
<StoryHeading as="h2" size="2xl">
{props.name}
</StoryHeading>
</Container>
{isOneChild ? children : <Storybook.SideBySide>{children}</Storybook.SideBySide>}
</Storybook.Section>
{isOneChild ? children : <SideBySide>{children}</SideBySide>}
</Section>
);
}
2 changes: 1 addition & 1 deletion static/app/stories/view/storyExports.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ function StoryLayout() {
);
}

export function makeStorybookDocumentTitle(title: string | undefined): string {
function makeStorybookDocumentTitle(title: string | undefined): string {
return title ? `${title} — Scraps` : 'Scraps';
}

Expand Down
55 changes: 51 additions & 4 deletions static/app/stories/view/useStoriesLoader.tsx
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Original file line number Diff line number Diff line change
@@ -1,10 +1,56 @@
import type React from 'react';
import {useMemo} from 'react';
import {useMemo, useSyncExternalStore} from 'react';

import {useQuery, type UseQueryResult} from 'sentry/utils/queryClient';

const context = require.context('sentry', true, /\.stories.tsx$/, 'lazy');
const mdxContext = require.context('sentry', true, /\.mdx$/, 'lazy');
let context = import.meta.webpackContext('sentry', {
recursive: true,
regExp: /\.stories.tsx$/,
mode: 'lazy',
});
let mdxContext = import.meta.webpackContext('sentry', {
recursive: true,
regExp: /\.mdx$/,
mode: 'lazy',
});

// External store that increments whenever HMR replaces a story or mdx file.
// Accepting context module IDs creates proper HMR boundaries — without this,
// updates are silently dropped or cause "unexpected require from disposed module".
let _storiesHmrVersion = 0;
const _storiesHmrListeners = new Set<() => void>();

if (process.env.NODE_ENV === 'development' && import.meta.webpackHot) {
const onUpdate = () => {
// Re-capture and re-register after each replacement — the old context
// reference is stale and its replacement won't have accept handlers.
context = import.meta.webpackContext('sentry', {
recursive: true,
regExp: /\.stories.tsx$/,
mode: 'lazy',
});
mdxContext = import.meta.webpackContext('sentry', {
recursive: true,
regExp: /\.mdx$/,
mode: 'lazy',
});
import.meta.webpackHot!.accept(context.id as string, onUpdate);
import.meta.webpackHot!.accept(mdxContext.id as string, onUpdate);
_storiesHmrVersion++;
_storiesHmrListeners.forEach(l => l());
};
Comment on lines +31 to +41
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@sentry sentry bot Feb 28, 2026

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Bug: The useStoryBookFiles hook uses useMemo with an empty dependency array, causing it to return a stale list of stories after an HMR update.
Severity: MEDIUM

Suggested Fix

Add the hmrVersion variable to the dependency array of the useMemo call within the useStoryBookFiles hook. This will ensure the list of story files is re-calculated whenever an HMR update occurs, similar to the pattern used in useStoriesLoader.

Prompt for AI Agent 
Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: static/app/stories/view/useStoriesLoader.tsx#L24-L41

Potential issue: The `useStoryBookFiles` hook memoizes its result using `useMemo` with
an empty dependency array. During a Hot Module Replacement (HMR) update, the
module-level variables `context` and `mdxContext` are reassigned with new story data.
However, since the `useMemo` has no dependencies, it doesn't re-evaluate and continues
to return the cached, stale list of story files from before the HMR update. As a result,
any new or modified stories will not appear in the story list sidebar until a full page
refresh is performed, undermining the HMR functionality.

Did we get this right? 👍 / 👎 to inform future reviews.

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@scttcper scttcper Feb 28, 2026 •
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conflates two different scenarios: file modification (what HMR handles) vs. file addition/deletion (what requires a full rebuild).

The only scenario where useMemo([]) would matter is "I added a new story file and want it to appear without refreshing" — but that's not an HMR scenario,
it's a full rebuild. After the rebuild the component remounts anyway and the memo re-runs.

import.meta.webpackHot.accept(context.id as string, onUpdate);
import.meta.webpackHot.accept(mdxContext.id as string, onUpdate);
}

function subscribeToStoriesHmr(listener: () => void) {
_storiesHmrListeners.add(listener);
return () => _storiesHmrListeners.delete(listener);
}

function getStoriesHmrVersion() {
return _storiesHmrVersion;
}

export interface StoryResources {
a11y?: Record<string, string>;
Expand Down Expand Up @@ -78,8 +124,9 @@ interface UseStoriesLoaderOptions {
export function useStoriesLoader(
options: UseStoriesLoaderOptions
): UseQueryResult<StoryDescriptor[], Error> {
const hmrVersion = useSyncExternalStore(subscribeToStoriesHmr, getStoriesHmrVersion);
return useQuery({
queryKey: [options.files],
queryKey: [options.files, hmrVersion],
queryFn: (): Promise<StoryDescriptor[]> => {
return Promise.all(options.files.map(importStory));
},
Expand Down
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