Clear path pattern in HandlerMapping

This commit refactors cb2b141d31 to move
the cleaning code from a DeferredResultProcessingInterceptor to the
RouterFunctionMapping.

See gh-26239

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultAsyncServerResponse.java

@@ -40,11 +40,8 @@ import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
-import org.springframework.web.context.request.NativeWebRequest;
-import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.async.AsyncWebRequest;
 import org.springframework.web.context.request.async.DeferredResult;
-import org.springframework.web.context.request.async.DeferredResultProcessingInterceptor;
 import org.springframework.web.context.request.async.WebAsyncManager;
 import org.springframework.web.context.request.async.WebAsyncUtils;
 import org.springframework.web.servlet.ModelAndView;
@@ -57,16 +54,6 @@ import org.springframework.web.servlet.ModelAndView;
  */
 final class DefaultAsyncServerResponse extends ErrorHandlingServerResponse implements AsyncServerResponse {
 
-	private static final DeferredResultProcessingInterceptor CLEAR_PATTERN_ATTRIBUTE_INTERCEPTOR =
-			new DeferredResultProcessingInterceptor() {
-				@Override
-				public <T> void postProcess(NativeWebRequest request, DeferredResult<T> deferredResult,
-						Object concurrentResult) {
-					request.removeAttribute(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE,
-							RequestAttributes.SCOPE_REQUEST);
-				}
-			};
-
 	static final boolean reactiveStreamsPresent = ClassUtils.isPresent(
 			"org.reactivestreams.Publisher", DefaultAsyncServerResponse.class.getClassLoader());
 
@@ -141,7 +128,6 @@ final class DefaultAsyncServerResponse extends ErrorHandlingServerResponse imple
 		WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
 		AsyncWebRequest asyncWebRequest = WebAsyncUtils.createAsyncWebRequest(request, response);
 		asyncManager.setAsyncWebRequest(asyncWebRequest);
-		asyncManager.registerDeferredResultInterceptors(CLEAR_PATTERN_ATTRIBUTE_INTERCEPTOR);
 		try {
 			asyncManager.startDeferredResultProcessing(deferredResult);
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/function/support/RouterFunctionMapping.java

@@ -189,7 +189,7 @@ public class RouterFunctionMapping extends AbstractHandlerMapping implements Ini
 	protected Object getHandlerInternal(HttpServletRequest servletRequest) throws Exception {
 		if (this.routerFunction != null) {
 			ServerRequest request = ServerRequest.create(servletRequest, this.messageConverters);
-			servletRequest.setAttribute(RouterFunctions.REQUEST_ATTRIBUTE, request);
+			setAttributes(servletRequest, request);
 			return this.routerFunction.route(request).orElse(null);
 		}
 		else {
@@ -197,4 +197,9 @@ public class RouterFunctionMapping extends AbstractHandlerMapping implements Ini
 		}
 	}
 
+	private void setAttributes(HttpServletRequest servletRequest, ServerRequest request) {
+		servletRequest.removeAttribute(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE);
+		servletRequest.setAttribute(RouterFunctions.REQUEST_ATTRIBUTE, request);
+	}
+
 }