Frame-arguments-06.js

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// Test extracting frame.arguments element getters and calling them in

// various awkward ways.

load(libdir + "asserts.js");

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

var dbg = Debugger(g);

var hits = 0;

var fframe, farguments, fgetter;

dbg.onDebuggerStatement = function (frame) {

    if (hits === 0) {

        fframe = frame;

        farguments = frame.arguments;

        fgetter = Object.getOwnPropertyDescriptor(farguments, "0").get;

        assertEq(fgetter instanceof Function, true);

        // Calling the getter without an appropriate this-object

        // fails, but shouldn't assert or crash.

        assertThrowsInstanceOf(function () { fgetter.call(Math); }, TypeError);

    } else {

        // Since fframe is still on the stack, fgetter can be applied to it.

        assertEq(fframe.onStack, true);

        assertEq(fgetter.call(farguments), 100);

        // Since h was called without arguments, there is no argument 0.

        assertEq(fgetter.call(frame.arguments), undefined);

    hits++;

};

g.eval("function h() { debugger; }");

g.eval("function f(x) { debugger; h(); }");

g.f(100);

assertEq(hits, 2);

// Now that fframe is no longer live, trying to get its arguments should throw.

assertEq(fframe.onStack, false);

assertThrowsInstanceOf(function () { fgetter.call(farguments); }, Error);