Incompatibility of spring-security 5.7 and 5.8 with reactor-core 3.5.0

[bergerst]

Describe the bug
In #11194, the Mono.subscriberContext() and Flux.subscriberContext() calls were replaced since they were removed with reactor-core 3.5.0.

But right now, there is no released spring-security version compatible with 3.5.0 as the PR was not back-ported.

The replacement method .contextWrite() exists since reactor 3.4.0, so there should be no issue with back-porting the fix.

To Reproduce
Set reactor-core to 3.5.0 in spring-security 5.7.x or 5.8.x, https://github.com/spring-projects/spring-security/blob/5.7.5/config/src/main/java/org/springframework/security/config/web/server/ServerHttpSecurity.java#L3239 will not compile.

Expected behavior
spring-security 5.7 and 5.8 should be compatible with reactor-core 3.5.0.

Sample

See the To Reproduce section.

[marcusdacoregio]

Hi @bergerst, thanks for reaching out.

See this comment where I explain why I think we shouldn't update the dependency to a minor version.

[bergerst]

It was clarified here that netty-reactor 1.1.x should be used with Spring Boot 3, therefore I'll stay on 2020: reactor/reactor-netty#2581