Backward compatibility issue in 3.6.0 release

[Vlad Rozov]

Hi All,

There is a possible change in operators behavior caused by changes that 
were introduced in the release 3.6.0 into DefaultInputPort and 
DefaultOutputPort. Please see 
https://issues.apache.org/jira/browse/APEXCORE-722. We need to agree how 
to proceed.

1. Break semantic versioning for the Default Input and Output Ports in 
the next release (3.7.0), declare protected variables as private and 
provide protected access method. Another option is to rename protected 
variables to use less common names (for example __count).
2. Keep protected variables with the risk that the following common 
operator design pattern will be used accidentally by existing operators 
and newly designed operators:

public Operator extends BaseOperator {
  private int count;
  public DefaultInputPort in = new DefaultInputPort() {
    @Override
    public void process(Object tuple)
    {
       count++;  // updates DefaultInputPort count, not Operator count!
    }
  }
}


Thank you,

Vlad