fix: remove redundant route.Hosts to prevent false diffs in ADC sync

The translator was setting hosts on both Route and Service for ApisixRoute
resources. Since both APISIX and API7 EE backends support service-level
hosts for route matching (APISIX routes inherit hosts from their parent
service), the route-level hosts is redundant.

For backends that don't support route-level hosts (e.g., API7 EE where
hosts is a service-level concept), this causes a false diff every sync
cycle: the local state has route.hosts but the remote state never will,
triggering unnecessary PUT requests and audit log bloat.

Remove route.Hosts assignment; service.Hosts remains as the canonical
location for host matching.

Ref: api7/rfcs#2
Ref: api7/adc#427

Author: jarvis9443

internal/adc/translator/apisixroute.go

@@ -192,7 +192,6 @@ func (t *Translator) buildRoute(ar *apiv2.ApisixRoute, service *adc.Service, rul
 		route.EnableWebsocket = *enableWebsocket
 	}
 	route.FilterFunc = rule.Match.FilterFunc
-	route.Hosts = rule.Match.Hosts
 	route.Methods = rule.Match.Methods
 	route.Plugins = plugins
 	route.Priority = ptr.To(int64(rule.Priority))

internal/adc/translator/apisixroute_test.go

@@ -0,0 +1,84 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package translator
+
+import (
+	"testing"
+
+	"github.com/go-logr/logr"
+	"github.com/stretchr/testify/assert"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	adc "github.com/apache/apisix-ingress-controller/api/adc"
+	apiv2 "github.com/apache/apisix-ingress-controller/api/v2"
+)
+
+func TestBuildRoute_HostsNotSet(t *testing.T) {
+	translator := NewTranslator(logr.Discard())
+
+	ar := &apiv2.ApisixRoute{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-route",
+			Namespace: "default",
+		},
+	}
+
+	service := &adc.Service{}
+	rule := apiv2.ApisixRouteHTTP{
+		Name: "rule1",
+		Match: apiv2.ApisixRouteHTTPMatch{
+			Hosts: []string{"example.com", "foo.com"},
+			Paths: []string{"/api/*"},
+		},
+	}
+
+	var enableWebsocket *bool
+	translator.buildRoute(ar, service, rule, nil, nil, nil, &enableWebsocket)
+
+	assert.Len(t, service.Routes, 1)
+	route := service.Routes[0]
+	// route.Hosts should NOT be set — hosts belong on Service, not Route.
+	// Setting hosts on Route causes false diffs in backends that don't
+	// support route-level hosts (e.g., API7 EE).
+	assert.Nil(t, route.Hosts, "route.Hosts should not be set; hosts should only be on Service")
+	assert.Equal(t, []string{"/api/*"}, route.Uris)
+}
+
+func TestBuildService_HostsSet(t *testing.T) {
+	translator := NewTranslator(logr.Discard())
+
+	ar := &apiv2.ApisixRoute{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-route",
+			Namespace: "default",
+		},
+	}
+
+	rule := apiv2.ApisixRouteHTTP{
+		Name: "rule1",
+		Match: apiv2.ApisixRouteHTTPMatch{
+			Hosts: []string{"example.com", "foo.com"},
+			Paths: []string{"/api/*"},
+		},
+	}
+
+	service := translator.buildService(ar, rule, 0)
+
+	// service.Hosts SHOULD be set — this is the canonical location for hosts.
+	assert.Equal(t, []string{"example.com", "foo.com"}, service.Hosts)
+}