Mqtt: publish pointer values (#13741)

server/mqtt.go

@@ -107,9 +107,12 @@ func (m *MQTT) publishComplex(topic string, retained bool, payload interface{})
 		}
 
 	case reflect.Pointer:
-		if reflect.ValueOf(payload).IsNil() {
-			payload = nil
+		if !reflect.ValueOf(payload).IsNil() {
+			m.publishComplex(topic, retained, reflect.Indirect(reflect.ValueOf(payload)).Interface())
+			return
 		}
+
+		payload = nil
 		fallthrough
 
 	default:

server/mqtt_test.go

@@ -42,15 +42,25 @@ func TestPublishTypes(t *testing.T) {
 	}{
 		Foo: "bar",
 	})
-	require.Len(t, topics, 1)
-	assert.Equal(t, `test/foo`, topics[0], "struct mismatch")
-	assert.Equal(t, `bar`, payloads[0], "struct mismatch")
+	assert.Equal(t, []string{"test/foo"}, topics, "struct mismatch")
+	assert.Equal(t, []string{"bar"}, payloads, "struct mismatch")
+	reset()
+
+	i := 1
+	m.publish("test", false, struct {
+		Foo, Bar *int
+	}{
+		Foo: &i,
+		Bar: nil,
+	})
+	assert.Equal(t, []string{"test/foo", "test/bar"}, topics, "pointer mismatch")
+	assert.Equal(t, []string{"1", ""}, payloads, "pointer mismatch")
 	reset()
 
 	slice := []int{10, 20}
 	m.publish("test", false, slice)
 	require.Len(t, topics, 3)
-	assert.Equal(t, []string{`test`, `test/1`, `test/2`}, topics, "slice mismatch")
-	assert.Equal(t, []string{`2`, `10`, `20`}, payloads, "slice mismatch")
+	assert.Equal(t, []string{"test", "test/1", "test/2"}, topics, "slice mismatch")
+	assert.Equal(t, []string{"2", "10", "20"}, payloads, "slice mismatch")
 	reset()
 }