Spring PathPattern#combine throws StringIndexOutOfBoundsException

Situation I've had the situation that a @Controller was defined with @RequestMapping("/*") to manage all request for that Dispatcher (that already defined urlPatterns="/main/something/*" to distinguish from other dispatcher). Now, when the Dispatcher was initializing it was throwing StringIndexOutOfBoundsException for a method in that Controller with a @GetMapping(value = "/x/{val}") mapping defined.

*Root cause I could drill this down to PathPattern:combine ... also reproducible by adding this case to spring-web/src/test/java/org/springframework/web/util/pattern/PathPatternTests.java:combine

assertThat(pathMatcher.combine("/*", "/x/y")).isEqualTo("/x/y");

Workaround Currently I've solved it by defining the @Controller with a @RequestMapping(/**) for matching multiple path segments (as I assume it's intended).

Enhancement I am unsure whether it's - an enhancement request for a better exception OR - a bug in combine when instead of endsWithSeparatorWildcard it's equal to the wildcard

:)

Comment From: DhruvTheDev1

So PathPattern.combine is expecting a pattern ending with /* but doesn't handle / properly which causes the StringIndexOutOfBoundsException - which is a runtime exception.

Hence, possibly a bug as it crashs when combining /* and /x/y.