CommandSpec injected into Mixins doesn't have a CommandLine

[zegelin]

When a CommandSpec is injected into a @Mixin class, the CommandSpec.commandLine() method returns null.

This prevents custom setter methods from throwing ParameterExceptions, since the exception constructor requires a not-null CommandLine object.

    static class ExampleMixin {
        @Spec CommandSpec spec;

        @Option(names = "--trex")
        void setTRexFences(final String value) {
            throw new CommandLine.ParameterException(spec.commandLine(), "Didn't say the magic word.");
        }
    }

    static class ExampleCommand implements Callable<Void> {
        @Spec CommandSpec spec;

        @Option(names = "--raptor")
        void setRaptorFences(final String value) {
            throw new CommandLine.ParameterException(spec.commandLine(), "Didn't say the magic word.");
        }

        @Mixin
        ExampleMixin mixin;

        @Override
        public Void call() throws Exception {
            return null;
        }
    }

    public static void main(String[] args) {
        CommandLine.call(new ExampleCommand(), args);
    }

When run with --raptor off (an option in the root Callable):

Didn't say the magic word.

When run with --trex off (an option in the mixin):

Could not invoke void com.zegelin.SpecRepro$ExampleMixin.setTRexFences(java.lang.String) with off

The InvocationTargetException cause is a NPE, from the assert @ CommandLine.java:8852, since the spec commandline is null.

Version: 3.5.0

[remkop]

Thanks for the bug report!
I overlooked this use case. :-(
I’ll look into it as soon as I can.

[remkop]

Fixed in master.
I will do a release for this now.

[remkop]

The fix is included in piococli-3.5.1. Enjoy!