MatDialog: cyclic dependency when using MatDialog in a HTTP_INTERCEPTORS

Bug (or odd edge case):

I use MatDialog in a HTTP_INTERCEPTORS to display a dialog if the HttpClient responds with a 401. This start causing “cyclic dependency” errors when HttpClient is a dependency for APP_INITIALIZER.

What is the expected behavior?

No “cyclic dependency” errors.

What is the current behavior?

This might happen due to the Overlay (used in MatDialog constructor) injecting the ApplicationRef that’s already imported by ApplicationModule . This error is thrown during resolving of deps for APP_INITIALIZER.

What are the steps to reproduce?

https://stackblitz.com/edit/angular-material2-issue-7vxrxf

[fredrikredflag]

You should be able to do something like this:

@Injectable()
export class UnauthorizedHook implements HttpInterceptor {
    private _dialog: MatDialog;
    private _injector: Injector;

    constructor (
        injector: Injector
    ) {
        this._injector = injector;
    }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        if (!this._dialog) {
            this._dialog = this._injector.get(MatDialog);
        }

        this._dialog.open(CustomErrorDialogComponent);
  }
}

[crisbeto]

Closing as a dupe of https://github.com/angular/material2/issues/10967 which will be fixed by https://github.com/angular/material2/pull/10975.