No longer sending real errors to _error.js on production builds.

[gcpantazis]

(Copying from #1800 since this is a new issue as a result of that cc/ @arunoda)

#1800 introduced a "fake error" object that's sent to the _error view on production. This creates a feature divergence on dev vs. production, and removed the possibility for tracking errors in getInitialProps.

My use case is that I want to send that error message to our logs, and the _error.js page is the best single place I see to capture errors that break next on both the client and server. i.e.:

export default class ErrorPage extends React.Component {
    static getInitialProps({res, jsonPageRes, err}) {
        if (err) {
            track.metric('render_error');
            // Utility method that serializes JS errors on client and server, sends them to logs
            track.error(err);
        }

        return {}
    }

    render() {
        return (
            <div>...</div>
        )
    }
}

If we're not consistently sending the error object to the error page, do we have a better way to grab and track them?

[arunoda]

Answered here: #1800 (comment)

[gcpantazis]

Okay, a few questions / points:

1. These aren't necessarily just server errors, since the apps are universally rendered.
2. Since this was removed, is there any one place in the application to predictably get all errors from next? Ideally it'd be the same server and client. I've gone through the source and it isn't really clear how errors are supposed to be handled.

[sethsamuel]

This is causing some serious problems for us, since Googlebot is triggering a mysterious client-side error when trying to render our pages, and we have not way of debugging it.

[gcpantazis]

Just wanted to bump this up; I'm still relying on a fork to get this functionality in. I'm guessing there isn't a better prescribed way to track errors in production yet since the serializeErrors method in server/render is still gated on dev.

I'm happy to send in a PR if we can agree on the right way to proceed; a next config option to send along the errors in production, perhaps?

cc/ @sergiodxa @arunoda @timneutkens

[gcpantazis]

This was fixed as of 4.1.4, closing

[timneutkens]

Awesome @gcpantazis