MacOS – When upgrading to Yosemite from Mavericks are there any traps with Brew and Ports

Moving data is dependant on the application that manages it, e.g. if it's a database you could do a dump and restore it on the new installation, if it's a configuration file just copy it, etc.

HomeBrew packages create the config files for launchd in the Cellar (read: formula's install dir) and at the end of the install process display an how-to install those files (the caveats method in formulas source) which generally is a simple cp and launchctl sequence.

Creating formulas is indeed easy, and the developers will happily accept your new or updated formulas. The process is,

In summary: fork, clone, create, commit, push, audit (new-formula)

Last but not least: take a look at the wiki.

macports.org currently says: "Note for Lion users: There is no official release supporting Mac OS X 10.7 yet, but you can test the MacPorts 2.0.0 release candidate if you like."

I usually don't upgrade to a new major version of OS X until MacPorts has released their first official support for it.

I agree with Jerry Jacobs that you should probably back up your /opt hierarchy before attempting. Then you could try doing sudo port selfupdate to see if that upgrades you from 1.9.2 (or whatever) to the 2.0.0 release candidate. If it does, then you can try sudo upgrade outdated.

I wouldn't try doing a sudo upgrade outdated on Lion without at least being on the 2.0.0 release candidate of MacPorts.