@RequestMapping negated header filters are not evaluated correctly

[ccmtaylor]

negated header expressions are not evaluated correctly. I have these two controller methods:

@RequestMapping(method = RequestMethod.POST, headers="content-type!=application/xml")
public String create(...) {
...
}

@RequestMapping(method = RequestMethod.POST, headers="content-type=application/xml")
public ResponseEntity<String> create(...) {
...
}

If the content-type header on the request is set to application/xml, the first controller is invoked.

Using a debugger, I've traced this to faulty logic in ServletAnnotationMappingUtils.checkHeaders():
For the first method, the variable 'found' is true and the variable 'negated' is true for a request with the header "Content-Type: application/xml". However, the check

if(!found) {
    return negated;
}

causes the enclosing loop to continue, so that the method eventually ends up at the

return true;

on the last line, causing the wrong result to be returned.

ServletAnnotationMappingUtils.checkHeaders (correctly) also returns true for the second controller method. Control flow then returns to

AnnotationMethodHandlerAdapter$ServletHandlerMethodResolver.resolveHnadlerMethod

.

RequestSpecificMappingInfoComparator

and

Collections.sort

don't change the list of matches, so the first method is incorrectly returned as the controller method.

If I change my controller class and reverse the method definitions, the other create method is chosen. I suspect this bug can be reproduced by reversing the method definition order in

ServletAnnotationControllerTests$NegatedContentTypeHeadersController

, which should cause

ServletAnnotationControllerTests.negatedContentTypeHeaders

to fail.

I've re-opened SPR-7346 and added this post as a comment.