Fix updating the process-node map

cluster/leader.go

@@ -13,6 +13,7 @@ import (
 	"github.com/datarhei/core/v16/cluster/proxy"
 	"github.com/datarhei/core/v16/cluster/store"
 	"github.com/datarhei/core/v16/log"
+	"github.com/datarhei/core/v16/maps"
 	"github.com/datarhei/core/v16/restream/app"
 )
 
@@ -679,8 +680,7 @@ func (c *cluster) doSynchronize(emergency bool) {
 
 	opStack, _, reality := synchronize(wish, want, have, nodesMap, c.nodeRecoverTimeout)
 
-	if !emergency && len(opStack) != 0 {
-		// TODO: only apply a new map if there are actually changes
+	if !emergency && !maps.Equal(wish, reality) {
 		cmd := &store.Command{
 			Operation: store.OpSetProcessNodeMap,
 			Data: store.CommandSetProcessNodeMap{

maps/equal.go

@@ -0,0 +1,22 @@
+package maps
+
+// Equal returns whether two maps are equal, same keys and
+// same value for matching keys.
+func Equal[A, B comparable](a map[A]B, b map[A]B) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for akey, avalue := range a {
+		bvalue, ok := b[akey]
+		if !ok {
+			return false
+		}
+
+		if avalue != bvalue {
+			return false
+		}
+	}
+
+	return true
+}

maps/equal_test.go

@@ -0,0 +1,52 @@
+package maps
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestEqual(t *testing.T) {
+	a := map[string]string{
+		"foo": "bar",
+		"boz": "foz",
+	}
+
+	b := map[string]string{
+		"boz": "foz",
+		"foo": "bar",
+	}
+
+	require.True(t, Equal(a, b))
+	require.True(t, Equal(b, a))
+}
+
+func TestNotEqual(t *testing.T) {
+	a := map[string]string{
+		"foo": "bar",
+		"boz": "foz",
+	}
+
+	b := map[string]string{
+		"boz": "foz",
+	}
+
+	require.False(t, Equal(a, b))
+	require.False(t, Equal(b, a))
+
+	c := map[string]string{
+		"foo": "baz",
+		"boz": "foz",
+	}
+
+	require.False(t, Equal(a, c))
+	require.False(t, Equal(c, a))
+
+	d := map[string]string{
+		"foo": "bar",
+		"baz": "foz",
+	}
+
+	require.False(t, Equal(a, d))
+	require.False(t, Equal(d, a))
+}