v8/test/mjsunit/debug-liveedit-2.js

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


Debug = debug.Debug


eval(
    "function ChooseAnimal(p) {\n " +
    "  if (p == 7) {\n" + // Use p
    "    return;\n" +
    "  }\n" +
    "  return function Chooser() {\n" +
    "    return 'Cat';\n" +
    "  };\n" +
    "}\n"
);

var old_closure = ChooseAnimal(19);

assertEquals("Cat", old_closure());

var script = Debug.findScript(ChooseAnimal);

var orig_animal = "'Cat'";
var patch_pos = script.source.indexOf(orig_animal);
var new_animal_patch = "'Capybara' + p";

// We patch innermost function "Chooser".
// However, this does not actually patch existing "Chooser" instances,
// because old value of parameter "p" was not saved.
// Instead it patches ChooseAnimal.
var change_log = new Array();
Debug.LiveEdit.ApplyPatch(script, patch_pos, orig_animal.length, new_animal_patch, change_log);
print("Change log: " + JSON.stringify(change_log) + "\n");

var new_closure = ChooseAnimal(19);
// New instance of closure is patched.
assertEquals("Capybara19", new_closure());

// Old instance of closure is not patched.
assertEquals("Cat", old_closure());