[BUG] Invalid type inference for Sets of Enums

[yeikel]

I have the following parameter :

@Parameter(names = { "--roles"}, description = "List of roles separated by comma")
private Set<Relationship.TypeEnum> roles = new HashSet<>(Arrays.asList(Relationship.TypeEnum.values()));

And when I pass a Role as a String, for example --roles "SUPP", it creates a Set<String> instead of a Set<Relationship.TypeEnum>

This behavior does not happen with ArrayLists

[Harlan1997]

I will work on this issue.

[Harlan1997]

I wrote a test to reproduce this problem.

package com.beust.jcommander;

import org.testng.Assert;
import org.testng.annotations.Test;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class SetOfEnumTest {

    public enum Season{
        SPRING,
        SUMMER,
        AUTUMN,
        WINTER;
    }

    @Test
    public void testParse()
    {
        class Args {
            @Parameter(names = { "--season"}, description = "List of seasons separated by comma")
            private Set<Season> seasons = new HashSet<>();
        }
        Args args = new Args();
        JCommander.newBuilder()
                .addObject(args)
                .build()
                .parse("--season", "SPRING");
        Assert.assertEquals(Season.class, args.seasons.toArray()[0].getClass());
    }

    public static void main(String[] args) {
        new SetOfEnumTest().testParse();
    }
}

The result of this test is:

java.lang.AssertionError: expected [class java.lang.String] but found [class com.beust.jcommander.SetOfEnumTest$Season]
Expected :class java.lang.String
Actual   :class com.beust.jcommander.SetOfEnumTest$Season

[Harlan1997]

The cause of this problem is that the current approach to convertValue() in JCommander only considers List conversion. To fix it, convertValue() should consider other collections like Set().

if (type.isAssignableFrom(List.class)) -> if (type.isAssignableFrom(List.class) || type.isAssignableFrom(Set.class))
if (type.isAssignableFrom(List.class) && converter == null) -> if ((type.isAssignableFrom(List.class) || type.isAssignableFrom(Set.class)) && converter == null)

Then it will pass the test.