InertiaHandleRequest middleware bypassed when HTTP error occurs

Hi !

I am currently creating a project involving Inertia for the first time, and I came across a weir behavior. Indeed, I tried to create some custom HTTP error pages for 404, 501, etc., but I found out that my shared data setup in the InertiaHandleRequest middleware were not shared on error pages (see: https://inertiajs.com/error-handling for the backend implementation of error redirection).

The data that I wanted to have globally no matter the state of the app was containing:

app name
locale
available language for language selector
auth for navbar customization based on logged user

public function share(Request $request): array
{     
      return array_merge(parent::share($request), [
          'appName' => config('app.name'),
          'locale' => app()->getLocale(),
          'availableLocales' => config('app.available_locales'),
          'flash' => [
              'message' => $request->session()->get('message'),
              'success' => $request->session()->get('success'),
              'error' => $request->session()->get('error'),
          ],
          'auth' => function () use ($request) {
              return [
                  'user' => $request->user() ? [
                      'id' => $request->user()->id,
                      'email' => $request->user()->email,
                  ] : null,
              ];
          },
      ]);
  }

Those were never passed to my custom error view.

The workaround I found was to create a custom Laravel middleware called SharedDataMiddleware that share the most important data like auth, appName and locale, and register this middleware as a global middleware for all request no matter what kind.

protected $middleware = [
    // \App\Http\Middleware\TrustHosts::class,
    \App\Http\Middleware\TrustProxies::class,
    \Illuminate\Http\Middleware\HandleCors::class,
    \App\Http\Middleware\PreventRequestsDuringMaintenance::class,
    \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
    \App\Http\Middleware\TrimStrings::class,
    \Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull::class,
    \App\Http\Middleware\SharedDataMiddleware::class,
];

class SharedDataMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
     */
    public function handle(Request $request, Closure $next): Response
    {
        Inertia::share("appName", config("app.name"));
        Inertia::share("availableLocales", config("app.available_locales"));
        Inertia::share("locale", app()->getLocale());
        Inertia::share("auth", function () use ($request) {
            return [
                'user' => $request->user() ? [
                    'id' => $request->user()->id,
                    'email' => $request->user()->email,
                ] : null,
            ];
        });

        return $next($request);
    }
}

Is this a proper way to bypass the problem I have or is it not the recommended way ?

Please let me know if something is shady so I can fix my mistakes and continue with development.

Cheers.

inertiajs / inertia-laravel

InertiaHandleRequest middleware bypassed when HTTP error occurs #535