ZFS clones and snapshot... can't delete snapshot were clone is based on

Question

root@solaris [/] # zfs list -r
NAME   USED  AVAIL  REFER  MOUNTPOINT
home   100K  9,78G    21K  /datahome
root@solaris [/] # zpool list
NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
home  9,94G   108K  9,94G     0%  ONLINE  -
root@solaris [/] # zfs create home/test
root@solaris [/] # zfs snapshot home/test@today
root@solaris [/] # zfs clone home/test@today home/myclone
root@solaris [/] # zfs list -r
NAME              USED  AVAIL  REFER  MOUNTPOINT
home              138K  9,78G    23K  /datahome
home/myclone         0  9,78G    21K  /datahome/myclone
home/test          21K  9,78G    21K  /datahome/test
home/test@today      0      -    21K  -
root@solaris [/] # zfs promote home/myclone
root@solaris [/] # zfs list -r
NAME                 USED  AVAIL  REFER  MOUNTPOINT
home                 140K  9,78G    24K  /datahome
home/myclone          21K  9,78G    21K  /datahome/myclone
home/myclone@today      0      -    21K  -
home/test               0  9,78G    21K  /datahome/test
root@solaris [/] # zfs destroy home/myclone
cannot destroy 'home/myclone': filesystem has children
use '-r' to destroy the following datasets:
home/myclone@today
root@solaris [/] # zfs destroy home/myclone@today
cannot destroy 'home/myclone@today': snapshot has dependent clones
use '-R' to destroy the following datasets:
home/test
root@solaris [/] #Why can't I destroy a snapshot? home/myclone is now a volume that is not linked to home/test.
So I would expect to be able to delete the snapshot from myclone.
Maybe I misunderstand something about how this works or I have the wrong expectations.
I would expect a clone to be something like a copy that is independent of the volume being cloned.

Answer 1

The idea is that when you create a clone, it is lightweight and based on the snapshot. That's what makes it so fast. You're not copying every block in the filesystem. So the snapshot is what ties together the parent filesystem and the clone.
For the clone to be independent, you'd have to copy all the blocks. There's no option to do that within the clone process. So as long as both the parent filesystem and the clone filesystem are around, the snapshot has to exist as well.
Darren