puppetlabs/facter — pull request #651 by adrienthebo (2014-03-04 22:25:50+00:00)
Title: FACT-357 Raise errors when executing non-existent commands

The behavior of returning an empty string when a command cannot be run is surprising and makes it impossible to determine if a command failed to run or simply had no output. This pull request allows users to determine if an error should be raised on error, or if a default value should be returned instead. It also updates calling code to respect this new behavior.