puppetlabs/geppetto — pull request #40 by thallgren (2014-09-11 14:46:58+00:00)
Title: (GEP-164) Handle dropped support for operator += in 4.0

Add a preference that controls reporting when the deprecated
+= operator is used. The default setting for this preference
is 'warning'. The preference is hardcoded to error in when
using version 4.0.