jcommander

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Using variable arity parameters together with unknown options fails with

ParameterException: Expected a value after parameter -values

JCommander#isOption simply returns true when acceptUnknownOption is true, so DefaultVariableArity#processVariableArity always returns 0, since it thinks the arguments to the variable arity option are options.

This used to work in 1.60, where isOption checked if the option has a prefix.

Example code:

import com.beust.jcommander.JCommander;
import com.beust.jcommander.Parameter;

import java.util.List;

public class VarArity {
    @Parameter (names = "-values", variableArity = true)
    private List<String> values;
    @Parameter (names = "-foo")
    private boolean foo;
    @Parameter
    private List<String> files;

    public static void main(String[] args) {
        VarArity app = new VarArity();
        JCommander jCommander = new JCommander(app);
        jCommander.setAcceptUnknownOptions(true);
        jCommander.parse("-values", "one", "two", "-foo", "-bar", "foobar.txt");
    }
}

We just hit this when attempting to upgrade from 1.58.

Also, hit this when upgrading from 1.48 to 1.72.

Confirming on this side as well. Unfortunately in our situation we can't simply disable setAcceptUnknownOptions because we use a polymorphic command line parser.

        JCommander commander = JCommander.newBuilder().addObject(options).build();
        commander.setProgramName(CodegenCLI.class.getSimpleName());
        commander.setAcceptUnknownOptions(true);
        commander.parse(args);
        
        ModelBuilder modelBuilder = new ModelBuilder(options);
        APIModel apiModel = modelBuilder.build();
        AbstractGenerator<?> generator = getGenerator(options.getGeneratorClassName(), apiModel);
        try {
            generator.populateOptions(args);

Where populateOptions is:

    public void populateOptions(String[] commandLineArgs) {
        O options = createOptions();
        if (options != null) {
            commander = JCommander.newBuilder().addObject(options).build();
            commander.parse(commandLineArgs);
        }
        this.options = options;
    }

That is to say, the first pass we have unknown options which are subsequently included based on an input parameter causing a re-evaluation of the options. Nonetheless in the "generic" parser JCommander commander we have some variableArity=true arguments which are left broken.

Are there plans to fix this?

@cbeust, any plans?

Happy to accept a PR.

What does it mean to accept unknown options? I don't see anything in the documentation about it.

Edit: Leaving an explanation here in case others see this and didn't know: if accept unknown options is true, then passing an unknown parameter (e.g. "-bar" in the example that started this thread) will simply be ignored. If it is false, then an exception is thrown here