CFEngine > Scalar item in package_list_command => { ls } in rvalue is out of bounds (value should match pattern "?(/.*))

Problem

Whilst validating a cf-promises file, I received the following output.
$ cf-promises -f ./promises.cf
cf3> ./packages.cf:23,28: Scalar item in package_list_command => { ls } in rvalue is out of bounds (value should match pattern "?(/.*)), near token 'ls"'

The associated line is:
package_list_command => "ls -1 /your/directory"

Solution

Basically, the error is trying to tell us that the "ls" command must be fully qualified.

The associated line should read:
package_list_command => "/bin/ls -1 /your/directory"