运行时apt-get dist-upgrade显示，有零个包不是升级了。当我运行时，apt-get autoremove它通知我有两个可以升级的软件包。对我来说，这是违反直觉的。实际上安装了两个软件包测试可以升级，但不会升级，因为存在一些依赖性问题。
我使用的是 Debian 8.6。
我的问题是：为什么不apt-get dist-upgrade告诉我这两个软件包，但却apt-get autoremove告诉我？
root@host ~# apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
root@host ~# apt-get autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.