RE: Is there any plan to support partial checkout or submoudule improvement?

The <revspec> can be a tag. So you can easily create a wrapper script
to allow such things as

$ ./deploy.sh v1.2.3
$ ./deploy.sh HEAD
$ ./deploy.sh master
$ ./deploy.sh <sha1>

But it is an online services, I must take care, so I prefer the incremental
update to avoid overwriting deployment directory fully each time. Another
consideration, Full update also introduces the busy network traffic.

franky