From a (mostly) Ruby on Rails developer.
After doing the below everything seems to work (some of it worked before doing anything), including Ruby, Gems, RVM, Homebrew, VirtualBox/Vagrant VMs, Pow, tmux, git, vim.
- Did a full-disk backup that I can restore from
- Moved out
/usr/local
to avoid super slow install, per option 1 in https://jimlindley.com/blog/yosemite-upgrade-homebrew-tips/:sudo mv /usr/local ~/local
- Upgraded to Yosemite
- Restored
/usr/local
, per option 1 in https://jimlindley.com/blog/yosemite-upgrade-homebrew-tips/:sudo mv ~/local /usr