RouterFunction ignored when last predicate is not a PathPatternPredicate (detected with Webflux)

[christophejan]

Describe the bug

Currently, when the last RequestPredicate of a RouterFunction is not a PathPatternPredicate, the RouterFunction is ignored by Springdoc (detected with Webflux).

To Reproduce

Use SpringDocApp150Test after removing the empty string pattern for the get-users GET operation.

IE replace :

springdoc-openapi/springdoc-openapi-webflux-core/src/test/java/test/org/springdoc/api/app150/HelloRouter.java

Line 55 in 1b1e652

.GET("", HANDLER_FUNCTION, builder -> builder.operationId("get-users"))

with the following line :

    .GET(HANDLER_FUNCTION, builder -> builder.operationId("get-users"))

Current result : the get-users route is then missing from the resulting API documentation

Expected behavior

The RouterFunction should be present in the API documentation even in that usecase.

Additional context

1. As workaround, we can specify an empty string PathPatternPredicate as last RequestPredicate like on the test used to reproduce.
2. I think the current behavior is due to AbstractRouterFunctionVisitor. I think that part of the logic present in the following if block of code (i.e. calls to createRouterFunctionData method) should be moved to commonRoute method (it will not be easy) :
   

   springdoc-openapi/springdoc-openapi-common/src/main/java/org/springdoc/core/fn/AbstractRouterFunctionVisitor.java

   Line 118 in 1b1e652

   if (currentRouterFunctionDatas != null) {