Why two equivalent property are not equal in Groovy

Question

Please have a look at this simple code:

String.metaClass {
  getA = {delegate <<= delegate}
}

assert 'a'.a == 'a'.a

Result: Assertion failed: 
    assert 'a'.a == 'a'.a
               | |      |
               | false  aa
               aa

Why the result is FALSE?

I am working at Groovy 2.4.7 on Windows 7 SP1

Answer 1

LeftShift on a String in Groovy generates a StringBuffer (docs)

So 'a'.a == 'a'.a is trying to do equals on two StringBuffers.

You can't do that with StringBuffer as the equals method isn't overloaded, and just checks if they are the same instance