test/mjsunit/debug-script-breakpoints-closure.js

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// Flags: --expose-debug-as debug
// Get the Debug object exposed from the debug context global object.
Debug = debug.Debug

// Simple debug event handler which just counts the number of break points hit.
var break_point_hit_count = 0;

function listener(event, exec_state, event_data, data) {
  if (event == Debug.DebugEvent.Break) {
    break_point_hit_count++;
  }
};

// Add the debug event listener.
Debug.setListener(listener);

function makeClosure() {
  var x;
  return function() {
    return x;                // Breakpoint line ( #47 )
  };
}

// Create closure before break point is set.
var closure = makeClosure();

// The debugger triggers re-compilation.
assertEquals(0, Debug.scriptBreakPoints().length);
var scr = Debug.findScript(makeClosure);
var sbp = Debug.setScriptBreakPointById(scr.id, 47);
assertEquals(1, Debug.scriptBreakPoints().length);

// Ensure the closure actually triggers a break point hit.
closure();
assertEquals(1, break_point_hit_count);

// Remove script break point.
assertEquals(1, Debug.scriptBreakPoints().length);
Debug.clearBreakPoint(sbp);
assertEquals(0, Debug.scriptBreakPoints().length);