error-cause-copied.js

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// Test that the ErrorCopier copies the optional "cause" property of error objects.

let g = newGlobal({newCompartment: true});

let dbg = new Debugger(g);

let hits = 0;

dbg.onDebuggerStatement = function (frame) {

  hits++;

  // Use |getVariable()| so we can easily throw our custom error from the

  // with-statement scope.

  let caught;

  try {

    frame.environment.getVariable("x");

  } catch (e) {

    caught = e;

  // The ErrorCopier copied error, so |caught| isn't equal to |g.error|.

  assertEq(caught !== g.error, true);

  // Ensure the "cause" property is correctly copied.

  assertEq(caught.cause, g.cause);

};

// The error must be same-compartment with the debugger compartment for the

// ErrorCopier.

g.eval(`

  var cause = new Object();

  var error = new Error("", {cause});

`);

// Scope must be outside of debugger compartment to avoid triggering a

// DebuggeeWouldRun error.

let scope = {

  get x() {

    throw g.error;

};

g.eval(`

  function f(scope) {

    with (scope) {

      debugger;

`);

g.f(scope);

assertEq(hits, 1);