Composite Argument Groups: more informative error messages #744
Description
I'm using the following code to ilustrate the issue:
package test;
import java.util.List;
import picocli.CommandLine;
import picocli.CommandLine.ArgGroup;
import picocli.CommandLine.Command;
import picocli.CommandLine.Option;
public class ArgGroupsTest {
public static void main(String[] args) {
CommandLine cmd = new CommandLine(new TestCommand());
cmd.execute( "-v");
}
@Command(name = "ArgGroupsTest")
static class TestCommand implements Runnable {
@ArgGroup( exclusive = false, multiplicity = "2..3")
List<DataSource> datasource;
static class DataSource {
@Option(names = "-v", required = true)
static boolean aString;
}
@Override
public void run() {
// nothing to do here
}
}
}
Issue 1: If I'm running the code above with one argument only ("-v"), I'm getting an error message:
Error: Group: (-v) (-v) [-v] must be specified 2 times but was matched 1 times
Usage: ArgGroupsTest (-v) (-v) [-v]
-v
In general, the message is fine, however, there is still room for improvement: it's the group ('-v') that needs to be specified at least two times, currently, the message tells that you have to give (-v) (-v) [-v] three times, however. This is misleading IMHO, I would propose to come up with an error message like:
Error: Group (-v) was found only once, must be specified 2 times at least
Usage: ArgGroupsTest (-v) (-v) [-v]
-v
Issue 2: If I'm running the code with four arguments ("-v -v -v -v"), I'm getting an error message, too:
Error: expected only one match but got (-v) (-v) [-v]={-v -v -v} and (-v) (-v) [-v]={-v}
Usage: ArgGroupsTest (-v) (-v) [-v]
-v
I doubt whether this makes clear to the user what's wrong here.
In this case, I would propose to come up with an error message like:
Error: Group (-v) was found 4 times, must not be given more than 3 times
Usage: ArgGroupsTest (-v) (-v) [-v]
-v
Just my 2 cents, thanks for providing and continuously improving picocli.