NPE SpringLookupInitializer createLookup Spring-Vaadin 19+ - spring

Question

In trying to update to the latest version of Vaadin (20 at time of question), my application will not start due to NPE in the SpringLookupInitializer. When I was using Vaadin 19, which is where SpringLookupInitializer first started being used and I first started encountering the error I had to always use Spring-Vaadin 12.4.0 for the application to start up. The error seems to be coming from this change...
In 12.4.0 there is code in SpringLookupInitializer defined as:
#Override
protected Lookup createLookup(VaadinContext context,
Map<Class<?>, Collection<Class<?>>> services) {
WebApplicationContext appContext = getApplicationContext(context);
return new SpringLookup(appContext,
(spi, impl) -> instantiate(appContext, spi, impl), services);
}
private WebApplicationContext getApplicationContext(VaadinContext context) {
VaadinServletContext servletContext = (VaadinServletContext) context;
WebApplicationContext appContext = WebApplicationContextUtils
.getWebApplicationContext(servletContext.getContext());
if (appContext == null) {
// Spring behavior is always unbelievably surprising: under some
// circumstances {#code appContext} may be null even though the app
// context has been set via ApplicationContextAware: no idea WHY
ApplicationContextWrapper wrapper = context
.getAttribute(ApplicationContextWrapper.class);
appContext = wrapper == null ? null : wrapper.appContext;
}
return appContext;
}
It works this way because it is doing a check and correcting it before proceeding (basically what the comment says). In the newest version the getApplicationContext is removed and the check no longer performed
#Override
protected Lookup createLookup(VaadinContext context,
Map<Class<?>, Collection<Class<?>>> services) {
WebApplicationContext appContext = WebApplicationContextUtils
.getWebApplicationContext(
((VaadinServletContext) context).getContext());
return new SpringLookup(appContext,
(spi, impl) -> instantiate(appContext, spi, impl), services);
}
I am not using spring boot just MVC and everything works fine with the older spring-vaadin version. Is there a reason it no longer performs this check or something else that has been implemented that I can do to stop this from happening?
Thanks

Answer 1

Thanks for the report - it seems that those changes (in PR #740) have been overlooked for the latest versions of the Vaadin Spring add-on. We're going through the changes and making sure those get forward-ported and will be released soon for Vaadin 20 too.
For similar cases, when updating the Vaadin version breaks something, it is recommended to just directly open a new issue to the corresponding repository (like vaadin/spring or vaadin/flow) so it will be noticed immediately by the development team. Thanks
EDIT: The fix has been released in the Vaadin Spring add-on version 17.0.1. You can specify your project to explicitly use that version of vaadin-spring artifact. It will be included in Vaadin 20.0.2 release which is coming by next Monday 14th of June at latest.