Missing elements in set of ArgGroup

[oSumAtrIX]

The arguments -e "A" -e "B" -d "C" are parsed into a single Selection element within the selection set, where enabled.selector.name is set to "B" and disabled.selector.name is set to "C". However, I would expect three separate Selection elements: two for the enabled ArgGroup and one for the disabled ArgGroup, according to the following specification:

@ArgGroup(exclusive = false, multiplicity = "0..*")
private var selection = mutableSetOf<Selection>()

internal class Selection {
    @ArgGroup(exclusive = false, multiplicity = "0..*")
    internal var enabled: EnableSelection? = null

    internal class EnableSelection {
        @ArgGroup(multiplicity = "1")
        internal lateinit var selector: EnableSelector

        internal class EnableSelector {
            @CommandLine.Option(
                names = ["-e", "--enable"],
                description = ["Name of the patch."],
                required = true,
            )
            internal var name: String? = null

            @CommandLine.Option(
                names = ["--ei"],
                description = ["Index of the patch in the combined list of the supplied RVP files."],
                required = true,
            )
            internal var index: Int? = null
        }

        @CommandLine.Option(
            names = ["-O", "--options"],
            description = ["Option values keyed by option keys."],
            mapFallbackValue = CommandLine.Option.NULL_VALUE,
            converter = [OptionKeyConverter::class, OptionValueConverter::class],
        )
        internal var options = mutableMapOf<String, Any?>()
    }

    @ArgGroup(exclusive = false, multiplicity = "0..*")
    internal var disable: DisableSelection? = null

    internal class DisableSelection {
        @ArgGroup(multiplicity = "1")
        internal lateinit var selector: DisableSelector

        internal class DisableSelector {
            @CommandLine.Option(
                names = ["-d", "--disable"],
                description = ["Name of the patch."],
                required = true,
            )
            internal var name: String? = null

            @CommandLine.Option(
                names = ["--di"],
                description = ["Index of the patch in the combined list of the supplied RVP files."],
                required = true,
            )
            internal var index: Int? = null
        }
    }
}

[remkop]

Have you tried setting multiplicity = "1" on EnableSelection also?

    @ArgGroup(exclusive = false, multiplicity = "1") // not 0..*
    internal var enabled: EnableSelection? = null

[remkop]

In the code you show, you have multiplicity="0..*" on variables (Selection.enabled and Selection.disable) which can only take a single value (because their type is not an array nor a Collection).
Therefore, I suggest using multiplicity = "1" in the annotations for these variables.

If Selection.disable is optional, then use multiplicity = "0..1". (You are testing with -e "A" -e "B" -d "C", so I assume that disable is optional.)

After making that change, it seems to work as expected:
The result is 2 Selection objects, and the second of these has a DisableSelection for C.

...
    static class Selection {
        @ArgGroup(exclusive = false, multiplicity = "1" ) // not "0..*"
        EnableSelection enabled = null;

then, my test

        new CommandLine(userObject).parseArgs("-e", "A", "-e", "B", "-d", "C");
        System.out.println(userObject.selection);

prints this:

[Selection{enabled=EnableSelection{selector=EnableSelector{name='A', index=null}, options={}}, disable=null}, 
 Selection{enabled=EnableSelection{selector=EnableSelector{name='B', index=null}, options={}}, disable=DisableSelection{selector=DisableSelector{name='C', index=null}}}]

The result is 2 Selection objects, and the second of these has a DisableSelection for C. I believe this is correct.

The full (java)) code for my test is below (basically I just converted your kotlin to java):

package picocli;

import org.junit.Test;
import picocli.CommandLine.*;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertNotNull;

public class Issue2350 {
    @ArgGroup(exclusive = false, multiplicity = "0..*")
    private Set<Selection> selection = new LinkedHashSet<Selection>();

    static class Selection {
        @ArgGroup(exclusive = false, multiplicity = "1" ) // can not "0..*" on single-value variable
        EnableSelection enabled = null;

        static class EnableSelection {
            @ArgGroup(multiplicity = "1")
            EnableSelector selector;

            static class EnableSelector {
                @Option(names = {"-e", "--enable"}, description = "Name of the patch.", required = true)
                String name = null;

                @Option(names = {"--ei"}, description = "Index of the patch in the combined list of the supplied RVP files.", required = true)
                Integer index = null;

                @Override
                public String toString() {
                    return "EnableSelector{" + "name='" + name + '\'' + ", index=" + index +  '}';
                }
            }

            @Option(names = {"-O", "--options"}, description = "Option values keyed by option keys.", mapFallbackValue = Option.NULL_VALUE
                //converter = [OptionKeyConverter::class, OptionValueConverter::class]
            )
            Map<String, Object> options = new LinkedHashMap<String, Object>();

            @Override
            public String toString() {
                return "EnableSelection{" + "selector=" + selector + ", options=" + options + '}';
            }
        }

        @ArgGroup(exclusive = false, multiplicity = "0..1") // not 0..* on single-value variable
        DisableSelection disable = null;

        static class DisableSelection {
            @ArgGroup(multiplicity = "1")
            DisableSelector selector;

            static class DisableSelector {
                @Option(names = {"-d", "--disable"}, description = "Name of the patch.", required = true)
                String name = null;

                @Option(names = "--di", description = "Index of the patch in the combined list of the supplied RVP files.", required = true)
                Integer index = null;

                @Override
                public String toString() {
                    return "DisableSelector{" + "name='" + name + '\'' + ", index=" + index + '}';
                }
            }

            @Override
            public String toString() {
                return "DisableSelection{" + "selector=" + selector + '}';
            }
        }

        @Override
        public String toString() {
            return "Selection{" + "enabled=" + enabled + ", disable=" + disable + '}';
        }
    }

    @Test
    public void test1() {
        Issue2350 userObject = new Issue2350();
        new CommandLine(userObject).parseArgs("-e", "A", "-e", "B", "-d", "C");
        System.out.println(userObject.selection);

        assertEquals("selection.size", 2, userObject.selection.size());
        Iterator<Selection> iterator = userObject.selection.iterator();
        Selection selection1 = iterator.next();
        assertEquals("selection1.enabled.selector.name", "A", selection1.enabled.selector.name);
        assertNull("selection1.enabled.selector.index", selection1.enabled.selector.index);
        assertEquals("selection1.enabled.options", Collections.emptyMap(), selection1.enabled.options);
        assertNull("selection1.disable", selection1.disable);

        Selection selection2 = iterator.next();
        assertEquals("selection2.enabled.selector.name", "B", selection2.enabled.selector.name);
        assertNull("selection2.enabled.selector.index", selection2.enabled.selector.index);
        assertEquals("selection2.enabled.options", Collections.emptyMap(), selection2.enabled.options);

        assertNotNull("selection2.disable", selection2.disable);
        assertEquals("selection2.disable.selector.name", "C", selection2.disable.selector.name);
        assertNull("selection2.disable.selector.index", selection2.disable.selector.index);
    }
}