Properly proceed in filter processing when request is replaced

When a filter calls chain.proceed with a new request, that request should be used for further processing.
Replacing the request is still not fully working even with this change, so #5491 is not fully fixed. RoutingInBoundHandler still does not consider the new request, because most of the request processing happens before the filter is applied. In the test case of this patch, this manifests as the response text still being "initial" even though the request has been replaced.

http-server-netty/src/test/groovy/io/micronaut/http/server/netty/filters/FilterReplaceRequestSpec.groovy

@@ -0,0 +1,87 @@
+package io.micronaut.http.server.netty.filters
+
+import io.micronaut.context.ApplicationContext
+import io.micronaut.context.annotation.Requires
+import io.micronaut.http.HttpRequest
+import io.micronaut.http.MutableHttpResponse
+import io.micronaut.http.annotation.Controller
+import io.micronaut.http.annotation.Filter
+import io.micronaut.http.annotation.Get
+import io.micronaut.http.client.HttpClient
+import io.micronaut.http.filter.HttpServerFilter
+import io.micronaut.http.filter.ServerFilterChain
+import io.micronaut.runtime.server.EmbeddedServer
+import org.reactivestreams.Publisher
+import spock.lang.Specification
+
+class FilterReplaceRequestSpec extends Specification {
+    def 'test replaced http request is handled by next filter'() {
+        given:
+        def ctx = ApplicationContext.run(['spec.name': 'FilterReplaceRequestSpec'])
+        def server = ctx.getBean(EmbeddedServer)
+        server.start()
+        def client = ctx.createBean(HttpClient, server.URI)
+        def filter1 = ctx.getBean(Filter1)
+        def filter2 = ctx.getBean(Filter2)
+
+        when:
+        def resp = client.toBlocking().exchange("/initial", String)
+        then:
+        resp.body() == "initial"
+        filter1.filteredRequest.path == "/initial"
+        filter2.filteredRequest.path == "/filter1"
+
+        cleanup:
+        server.stop()
+        client.stop()
+    }
+
+
+    @Filter(Filter.MATCH_ALL_PATTERN)
+    @Requires(property = 'spec.name', value = 'FilterReplaceRequestSpec')
+    static class Filter1 implements HttpServerFilter {
+        HttpRequest<?> filteredRequest = null
+
+        @Override
+        int getOrder() {
+            1
+        }
+
+        @Override
+        Publisher<MutableHttpResponse<?>> doFilter(HttpRequest<?> request, ServerFilterChain chain) {
+            filteredRequest = request
+            return chain.proceed(HttpRequest.GET("/filter1"))
+        }
+    }
+
+    @Filter(Filter.MATCH_ALL_PATTERN)
+    @Requires(property = 'spec.name', value = 'FilterReplaceRequestSpec')
+    static class Filter2 implements HttpServerFilter {
+        HttpRequest<?> filteredRequest = null
+
+        @Override
+        int getOrder() {
+            2
+        }
+
+        @Override
+        Publisher<MutableHttpResponse<?>> doFilter(HttpRequest<?> request, ServerFilterChain chain) {
+            filteredRequest = request
+            return chain.proceed(HttpRequest.GET("/filter2"))
+        }
+    }
+
+    @Controller
+    @Requires(property = 'spec.name', value = 'FilterReplaceRequestSpec')
+    static class Ctrl {
+        @Get("/filter2")
+        def filter2() {
+            return "filter2"
+        }
+
+        @Get("/initial")
+        def initial() {
+            return "initial"
+        }
+    }
+}

http-server/src/main/java/io/micronaut/http/server/RouteExecutor.java

@@ -393,9 +393,9 @@ public Publisher<MutableHttpResponse<?>> proceed(io.micronaut.http.HttpRequest<?
                 }
                 HttpFilter httpFilter = filters.get(pos);
 
-                HttpRequest<?> requestForFilter = requestReference.getAndSet(request);
+                requestReference.set(request);
                 try {
-                    return Flux.from((Publisher<MutableHttpResponse<?>>) httpFilter.doFilter(requestForFilter, this))
+                    return Flux.from((Publisher<MutableHttpResponse<?>>) httpFilter.doFilter(request, this))
                             .flatMap(handleStatusException)
                             .onErrorResume(onError);
                 } catch (Throwable t) {