Migrate app data on upgrade

[Ryan Schmidt]

On Mar 23, 2009, at 16:04, C. Florian Ebeling wrote:

> Is there a working example of migrating app data to a new format in a
> some port? There are obviously a number of issues with doing something
> like this:
>
> - finding the source format version from a portfile with higher  
> version
> - finding app data from a range of versions in possibly a number of  
> locations
> - working with a number of formats from a higher version portfile,
> and previous (creating) versions possibly uninstalled
> - probably many others
>
> Are there good paths to follow? Is it worth doing? Is having
> version-specific (default) data directories a good idea (And then
> offering people export in old and import in new version, advertised by
> ui_msgs)? What do other distros do?

I don't think upgrading a port should upgrade any user data. If an  
upgrade of user data is necessary, the user should be advised how to  
do so, but it should be left to the user to do.