_error.js & _app.js: getInitialProps will only be call in _app.js but not in _error.js

[Zauberfisch]

Bug report

Describe the bug

If I create both _app.js and _error.js with each having a getInitialProps method, only the getInitialProps in _app.js will be called, but never the one in _error.js

To Reproduce

// pages/_app.js
function App({Component, pageProps}) {
	return <Component {...pageProps} />
}
App.getInitialProps = async () => {
	console.log('App.getInitialProps')
	return {}
}
export default App

// pages/_error.js
function Error(props) {
	return <div>
		<h1>_error.js</h1>
		<pre>{JSON.stringify({props})}</pre>
	</div>
}
Error.getInitialProps = () => {
	console.log('Error.getInitialProps')
	return {
		thisShouldBePassedToErrorComponent: 'but it is not unless you remove App.getInitialProps'
	}
}
export default Error

// pages/index.js
export default function Home() {
	return <h1>index.js</h1>
}
export function getServerSideProps() {
	throw "error in Home.getServerSideProps"
	return {props: {}}
}

1. visit / to get a 500 error or visit /non-existing-route to get a 404 error
2. the console will only show 'App.getInitialProps' but never Error.getInitialProps
3. remove App.getInitialProps from _app.js, now Error.getInitialProps will be called

Expected behavior

getInitialProps should be called in both, _app.js and _error.js

System information

• Version of Next.js: 9.5.5
• Version of Node.js: v14.12.0

[timneutkens]

This is a bug in your code, _app getInitialProps implements getInitialProps of pages:

App.getInitialProps = async ({Component, ctx}) => {
    let pageProps = {}

    if (Component.getInitialProps) {
      pageProps = await Component.getInitialProps(ctx)
    }

	return {pageProps}
}

[Zauberfisch]

Ah, indeed. It's there in the comments of the custom app example to call the parent getInitialProps.

Sorry about that

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.