Puppet

The following manifest:

$ cat foo.pp 
notice $a
exec{"/bin/echo a=$a > /tmp/foo": }

produced in 0.25.x the following:

$ puppet foo.pp
notice: Scope(Class[main]): 
notice: //Exec[/bin/echo a= > /tmp/foo]/returns: executed successfully
$ cat /tmp/foo
a=

However 2.6 produces:

$ puppet foo.pp
notice: Scope(Class[main]): undef
notice: /Stage[main]//Exec[/bin/echo a=undef > /tmp/foo]/returns: executed successfully
$ cat /tmp/foo
a=undef

This changes the behavior of various execs and generate functions. In regard to ruby’s behavior of nil.to_s undef variables should also be empty strings.

Otherwise this should be documented, but it will give some headaches in mixed enviornments.