[GSoC] migration

[Joshua Root]

On 2017-7-22 11:01 , Umesh Singla wrote:
> Another thing that comes to my mind now is if, suppose, updated version 
> of ncurses was actually required for some another port and reverting it 
> to the older state could possibly result in breaking of that port. May 
> be, we could get all the ports which depend on it and check if this 
> specific port requirement could be satisfied by its older versions as 
> well and then just ask the user if the user would like to restore or not?
> 
> Again, I'm not really aware of the things, so I'd like the inputs of 
> community here.

We don't have version dependencies so no, this sort of check is not 
possible a priori. Breakage will be caught by rev-upgrade after the fact 
in many cases (and if it is set to rebuild automatically, it may well 
revert you back to the newer version).

Also note that we can't actually revert to an older version of a port if 
it has been uninstalled.

- Josh