fix: implement comparable interface for ir.Infra to avoid multiple re…

…conciling (#2395)

internal/ir/infra.go

@@ -6,9 +6,12 @@
 package ir
 
 import (
+	"cmp"
 	"errors"
 	"fmt"
+	"reflect"
 
+	"golang.org/x/exp/slices"
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 
 	"github.com/envoyproxy/gateway/api/v1alpha1"
@@ -229,3 +232,20 @@ func (p *ProxyInfra) ObjectName() string {
 	}
 	return "envoy-" + p.Name
 }
+
+// Equal implements the Comparable interface used by watchable.DeepEqual to skip unnecessary updates.
+func (p *ProxyInfra) Equal(y *ProxyInfra) bool {
+	// Deep copy to avoid modifying the original ordering.
+	p = p.DeepCopy()
+	p.sort()
+	y = y.DeepCopy()
+	y.sort()
+	return reflect.DeepEqual(p, y)
+}
+
+// sort ensures the listeners are in a consistent order.
+func (p *ProxyInfra) sort() {
+	slices.SortFunc(p.Listeners, func(l1, l2 *ProxyListener) int {
+		return cmp.Compare(l1.Name, l2.Name)
+	})
+}

internal/ir/infra_test.go

@@ -8,6 +8,7 @@ package ir
 import (
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/stretchr/testify/require"
 )
 
@@ -211,3 +212,35 @@ func TestObjectName(t *testing.T) {
 		})
 	}
 }
+
+func TestEqualInfra(t *testing.T) {
+	tests := []struct {
+		desc  string
+		a     *ProxyInfra
+		b     *ProxyInfra
+		equal bool
+	}{
+		{
+			desc: "out of order proxy listeners are equal",
+			a: &ProxyInfra{
+				Listeners: []*ProxyListener{
+					{Name: "listener-1"},
+					{Name: "listener-2"},
+				},
+			},
+			b: &ProxyInfra{
+				Listeners: []*ProxyListener{
+					{Name: "listener-2"},
+					{Name: "listener-1"},
+				},
+			},
+			equal: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.desc, func(t *testing.T) {
+			require.Equal(t, tc.equal, cmp.Equal(tc.a, tc.b))
+		})
+	}
+}