Migrate app data on upgrade

[C. Florian Ebeling]

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?

Florian




-- 
Florian Ebeling
Twitter: febeling
florian.ebeling at gmail.com