Current status

Groovy 2.3 introduced traits - a code construct for composition of behaviours:

• http://docs.groovy-lang.org/latest/html/documentation/core-traits.html

Currently Clover handles them like an interface - it records the class name in a database but it does not instrument the class, so it shows no code coverage in reports for them.

Side note: Clover's reports by default do not show classes containing no executable code (empty classes, plain enums, interfaces with no default methods, traits) - you can show them by setting showEmpty=true parameter.

Proposed improvement

Instrument Groovy traits like normal classes or enums.

Side note: Groovy 2.5 will probably not introduce interfaces with default methods (like in Java 8).

• http://docs.groovy-lang.org/next/html/documentation/#_interface

Technical obstacles

• method '$CLV_R$' is private but should be public in a trait
• method 'com_atlassian_clover.CoverageRecorder $CLV_R$()' must not be static; only fields may be static in a trait
• field '$CLV_R$' is not 'public static final' in a trait