WebFlux.fn puts wrong type of HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE [SPR-17395]

[spring-projects-issues]

Toshiaki Maki opened SPR-17395 and commented

#21635 introduced RouterFunctions.MATCHING_PATTERN_ATTRIBUTE to WebFlux.fn, and set that mapping information as a String. #21900 duplicated that same information in HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE with the same type, whereas it is expected to be of type PathPattern,

spring-framework/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/support/RouterFunctionMapping.java

Lines 160 to 165 in 8de5c05

	attributes.put(BEST_MATCHING_HANDLER_ATTRIBUTE, handlerFunction);
	String matchingPattern =
	(String) attributes.get(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE);
	if (matchingPattern != null) {
	attributes.put(BEST_MATCHING_PATTERN_ATTRIBUTE, matchingPattern);

As a result, ClassCastException occurs after updating to Spring Boot 2.1.0.RC1 as Boot expects it as PathPattern

https://github.com/spring-projects/spring-boot/blob/v2.1.0.RC1/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/web/reactive/server/WebFluxTags.java#L97-L98

---

Affects: 5.1.1

Issue Links:

• Provide matched pattern information in WebFlux fn [SPR-17098] #21635 Provide matched pattern information in WebFlux fn
• Set BEST_MATCHING_HANDLER_ATTRIBUTE in WebFlux.fn [SPR-17367] #21900 Set BEST_MATCHING_HANDLER_ATTRIBUTE in WebFlux.fn

[spring-projects-issues]

Juergen Hoeller commented

Either we need to put a PathPattern there, or Boot needs to assume a String... Either way, this needs to be clarified for Spring Framework 5.1.2 / Boot 2.1 GA.

[spring-projects-issues]

Rossen Stoyanchev commented

The Javadoc only says "the best matching pattern" but should have say to expect PathPattern since that's what's in use in WebFlux and that's what was actually being set for annotated controllers since 5.0. So to let's make it official in the Javadoc and set to PathPattern consistently.

[spring-projects-issues]

Arjen Poutsma commented

Fixed in d303c8a