[jira] [Created] (CLI-284) Inconsistency in constraints for creating an instance of class Option using builder pattern or constructor

["Dilraj Singh (JIRA)" <ji...@apache.org>]

Dilraj Singh created CLI-284:
--------------------------------

             Summary: Inconsistency in constraints for creating an instance of class Option using builder pattern or constructor
                 Key: CLI-284
                 URL: https://issues.apache.org/jira/browse/CLI-284
             Project: Commons CLI
          Issue Type: Bug
            Reporter: Dilraj Singh


Builder pattern for creating an instance of class *Option* ensures that at least one of the representation (short and long representation) for the option is not null. It throws an *IllegalArgumentException* in-case program tries to build an instance with both the representations as null. Consider the following code snippet for reference.
{code:java}
public static void main(String[] args) {
  Option.Builder builder = Option.builder();
  Option op = builder.build();
} 
{code}
This piece of code fails with the following exception
{noformat}
Exception in thread "main" java.lang.IllegalArgumentException: Either opt or longOpt must be specified
{noformat}
But if we try to create an instance of Option by calling its constructor, It allows the creation with both opt and longOpt for Option as null. Consider the following code snippet for reference
{code:java}
public static void main(String[] args) {
  Option op = new Option(null, null);
  System.out.format("Short Representation: %s\n" +
  "Long Representation: %s", op.getOpt(), 
  op.getLongOpt());
}
{code}
Output:
{noformat}
Short Representation: null
Long Representation: null
{noformat}
Calling a method on an instance with both opt and longOpt as null will lead to undesired null pointer exception. For example, calling
{code:java}
 op.getId() {code}
will throw a null pointer exception, thus violating the method contract.

So as to fix this we need to make sure that whenever a constructor is invoked it has a non-null argument value for at least one of the Option representation. 



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