[GROOVY-3364] == operator does not work anymore if Comparable is implemented!

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.5.7, 1.6-rc-3
• Component/s: groovy-runtime
• Flags: Patch
• Assignee: Unassigned
• Reporter: Peter Rietzler
• Created: 18/Feb/09 06:51
• Updated: 05/Apr/15 14:44

Description

Once a class implements Comparable, the == operator does not work anymore!

class X implements Comparable {
  int compareTo(Object object) {
    return 0
  }
  boolean equals(Object object) {
    return true;
  }
}

public void testEqualityOperator() {
  def x = new X()
  def y = new Y()
  assert x == x   // OK 
  assert x == y // OK 
  assert x == 1 // FAIL - Neither compareTo() nor equals() is called!
}

The location of the bug is in

DefaultTypeTransform.compareToWithEqualityCheck(Object left, Object right, boolean equalityCheckOnly):

        if (equalityCheckOnly) {
            return -1; // anything other than 0
        }

The fix is:

        if (equalityCheckOnly) {
          return ((Boolean) InvokerHelper.invokeMethod(left, "equals", right)).booleanValue() ? 0 : -1;
        }

An even better fix would be to always use equals for the == operator - but this is already discussed in other issues.

I've set this to a BLOCKER beause this issue leads to the fact that I cannot use Groovy for relaxed typing - and that makes it useless for many DSLs!