Implicit return in Groovy switch statement is instrumented incorrectly

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    • Type: Bug
    • Resolution: Fixed
    • Priority: High
    • 3.2.0
    • Affects Version/s: None
    • Component/s: Instrumentation
    • None

      Problem:

      Consider the following code:

      def create(boolean b) {
        switch (b) {
            case true:
                new Integer(10)
                break
            case false:
                new String("abc")
                break
        }
}
      • switch statement is the last statement in function, so it's value is being returned from a function call
      • new Integer() / new String() are last statements before 'break' which is a function's exit point
      • thus 10 or "abc" are returned

      Clover instruments code as follows:

      def create(boolean b) { recorder.inc(0);
        switch (b) {
            case true:
                recorder.inc(1); new Integer(10)
                recorder.inc(2); break
            case false:
                recorder.inc(3); new String("abc")
                recorder.inc(4); break
        }
}
      • as a consequence, the last statement before 'break' becomes recorder.inc(), which returns void; as a result the create() function returns null

      Workaround:

      Use return instead of break in a switch statement, e.g.:

                  case true:
                return new Integer(10)
                // no break

      Fix:

      • do not add recorder.inc() before 'break'; drawback of the solution: we loose tracking of empty breaks, see below.
      def foo(int i) {
  switch (i) {
    case 1:
      recorder.inc(1); println("one")
      /*recorder.inc(2); not added*/ break;
    case 2:
    case 3: 
      /*recorder.inc(3); not added*/ break;
  }
}

foo(1)
foo(2)

      in the code above it would be nice to have "case2: case 3: recorder.inc(3); break;" colored in green, despite that code makes nothing ...

            Assignee:
            Marek Parfianowicz
            Reporter:
            Marek Parfianowicz
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              Created:
              Updated:
              Resolved: