ensure -> latest fails

[mnot]

If I have ensure => latest on a homebrew package, it now fails like this if already installed:

err: /Stage[main]/Base-brew/Package[git]/ensure: change from 1.7.9.2 to 1.7.10.1 failed: Could not update: Execution of '/usr/local/bin/brew install git' returned 1: Error: git-1.7.9.2 already installed
To install this version, first `brew unlink git'
 at /Users/mnot/Projects/puppet/manifests/base-osx.pp:63
err: /Stage[main]/Base-brew/Package[ruby]/ensure: change from 1.9.3-p125 to 1.9.3-p194 failed: Could not update: Execution of '/usr/local/bin/brew install ruby' returned 1: Error: ruby-1.9.3-p125 already installed
To install this version, first `brew unlink ruby'
 at /Users/mnot/Projects/puppet/manifests/base-osx.pp:72

brew -v
0.9

puppet --version
2.7.14

[jedi4ever]

Sorry I'm not using this for the moment. Will check later perhaps.