Webflux model in @GetMapping is empty

[dsyer]

This appears to be a regression (works with Spring Boot 2.3.0 and fails with 2.3.1). I think it's more likely to be a Webflux issue, but not really sure TBH. Consider this controller:

@Controller
public class SampleController {

	@GetMapping("/")
	public String home(Map<String, Object> model) {
		model.put("time", new Date());
		model.put("message", "Hello");
		return "index";
	}
}

The home() method is not called (I observe in a debugger) before the AbstractView is rendered, so the model is empty. Sample: https://github.com/scratches/SPR-25313.

UPDATE: it also works with Spring Boot 2.4.0-SNAPSHOT. So something is stuck in the middle there.

[sdeleuze]

I made various tests:

• It works with Boot 2.3.0.RELEASE and Framework 5.2.7.RELEASE
• Boot master and 2.3.x branches fixes the issue
• The issue does not happen if you rename the index view to something else or is you use a non-root path

It looks like a duplicate of spring-projects/spring-boot#21909, so I close this issue which is already fixed on Boot side.