[Bug]: getParser5() Ignores tsconfigPath Option

[endurance-chorus]

Describe the bug

Bug 1: getParser5() Ignores tsconfigPath Option

Summary

The getParser5() function in @storybook/react/dist/preset.js ignores the user-provided tsconfigPath option from reactDocgenTypescriptOptions and always uses findTsconfigPath(process.cwd()).

Impact

Users cannot specify a custom tsconfig for MCP manifest generation. This breaks:

• Solution-style monorepos where tsconfig.json has empty include/files arrays
• Projects needing different tsconfigs for different purposes (e.g., build vs. documentation)
• Aggregated Storybook setups with stories from multiple packages that need a unified tsconfig
• Custom tsconfig locations where the tsconfig isn't named tsconfig.json

Location

• File: @storybook/react/dist/preset.js
• Function: getParser5() (~line 11619)
• Source Location: Likely in @storybook/react source under /src/preset.ts or similar

Reproduction link

Please review anyway - the bug + suggested fix is very very clear.

Reproduction steps

Reproduction Steps

1. Create a solution-style TypeScript monorepo with root tsconfig.json:

   {
     "include": [],
     "files": [],
     "references": [
       { "path": "./packages/ui" },
       { "path": "./packages/app" }
     ]
   }

2. Create a separate tsconfig for Storybook documentation:

   // tsconfig.storybook.json
   {
     "extends": "./tsconfig.base.json",
     "include": ["packages/*/src/**/*.ts", "packages/*/src/**/*.tsx"]
   }

3. Configure Storybook with the custom tsconfig:

   // .storybook/main.ts
   const config: StorybookConfig = {
     typescript: {
       reactDocgen: 'react-docgen-typescript',
       reactDocgenTypescriptOptions: {
         tsconfigPath: './tsconfig.storybook.json',  // This is ignored!
       },
     },
   };

4. Run Storybook and check MCP manifest output

5. Observe: The custom tsconfig is ignored; manifest shows "No component file found" for all components

System

│
│  
│  Storybook Environment Info:
│

│  System:
│  OS: macOS 26.3.1
│  CPU: (16) arm64 Apple M4 Max
│  Shell: 5.9 - /bin/zsh
│  Binaries:
│  Node: 22.22.0 - /Users/enduranceidehen/.nvm/versions/node/v22.22.0/bin/node
│  Yarn: 1.22.22 - /Users/enduranceidehen/.nvm/versions/node/v22.22.0/bin/yarn
│  npm: 10.9.4 - /Users/enduranceidehen/.nvm/versions/node/v22.22.0/bin/npm
│  pnpm: 10.10.0 - /Users/enduranceidehen/.nvm/versions/node/v22.22.0/bin/pnpm
│  <----- active
│  Browsers:
│  Chrome: 146.0.7680.165
│  Safari: 26.3.1
│  npmPackages:
│  @storybook/addon-a11y: ^10.3.3 => 10.3.3
│  @storybook/addon-designs: ^11.1.3 => 11.1.3
│  @storybook/addon-docs: ^10.3.3 => 10.3.3
│  @storybook/addon-mcp: ^0.4.2 => 0.4.2
│  @storybook/addon-vitest: ^10.3.3 => 10.3.3
│  @storybook/react: 10.3.3 => 10.3.3
│  @storybook/react-vite: 10.3.3 => 10.3.3
│  @storybook/test-runner: 0.24.3 => 0.24.3
│  storybook: 10.3.3 => 10.3.3

Additional context

Current Behavior

function getParser5(userOptions) {
  let {
    shouldExtractLiteralValuesFromEnum,
    shouldRemoveUndefinedFromOptional,
    shouldIncludePropTagMap,
    savePropValueAsString,
    skipChildrenPropWithoutDoc,
    propFilter,
    shouldIncludeExpression,
    customComponentTypes
  } = {
    ...defaultOptions,
    ...userOptions
  };
  
  // BUG: Always uses findTsconfigPath, ignoring userOptions.tsconfigPath!
  let configPath = findTsconfigPath(process.cwd());
  
  // userOptions.tsconfigPath is destructured but NEVER used
  // ...
}

Expected Behavior

The function should respect user-provided tsconfigPath:

function getParser5(userOptions) {
  let {
    shouldExtractLiteralValuesFromEnum,
    shouldRemoveUndefinedFromOptional,
    shouldIncludePropTagMap,
    savePropValueAsString,
    skipChildrenPropWithoutDoc,
    propFilter,
    shouldIncludeExpression,
    customComponentTypes,
    tsconfigPath  // Destructure this!
  } = {
    ...defaultOptions,
    ...userOptions
  };
  
  // Use user-provided tsconfigPath if available
  let configPath = tsconfigPath 
    ? path.resolve(process.cwd(), tsconfigPath)
    : findTsconfigPath(process.cwd());
  
  // ...
}

Debugging Evidence

When adding console logging to the bundled code:

// In getParser5()
console.log('userOptions:', userOptions);
console.log('userOptions.tsconfigPath:', userOptions.tsconfigPath);  // Shows the path
console.log('configPath used:', configPath);  // Shows different path from findTsconfigPath()

Workaround

Modify the root tsconfig.json (the one found by findTsconfigPath()) to include all necessary source files directly, bypassing the solution-style pattern.

Suggested Fix

In the Storybook source code, update getParser5() to destructure and use tsconfigPath from userOptions.

[endurance-chorus]

Apologies, i dont have extra time to put together a repo that demonstrates it. Please let me know if you need more context - I hope this was clear.