// Regression test for issue #633: Stack-overflow due to infinite recursion
// in user-defined operator (string interpolation).
//
// Before the fix the recursive `/=` invocation triggered unbounded native
// recursion in the evaluator and crashed the host process with a SIGSEGV.
// The engine now bounds call_depth and throws a catchable exception
// instead of letting the native stack overflow.

def string::`/=`(double d) {
  this = "${this/= 2}/=${d}";
  return this;
}

var s = "o World"
var caught = false
var message = ""

try {
  s /= 2
  // unreachable: the recursive operator must abort with an exception
  assert_true(false)
} catch (e) {
  caught = true
  message = e.what()
}

assert_true(caught)

// The reported error must mention the call-stack overflow so users can
// distinguish it from an arbitrary script-level error.
assert_true(find(message, "call stack") != -1)

// A bounded recursion that stays well below the limit must keep working.
// Use a small depth so the test passes on every platform default - notably
// the MSVC Debug build where the native stack budget forces a tighter cap.
def count_down(n) {
  if (n <= 0) { return 0 }
  return count_down(n - 1) + 1
}

assert_equal(10, count_down(10))