Array missing element about jalangi

[ksen007]

This is not a bug, but an expected behavior of Jalangi. We treat Array.push() as a native function in Jalangi. The method is called during recording, but is skipped during replay. Replay recreates the array x as it's elements are accessed. For example, the following code will give the correct output.

var x = new Array()
function f() {
x.push({p: "foo"});
console.log(x[0]);
console.log(x);
}
f()

If you do not want to skip the push method of Array during replay, you can modify the function getSymbolicFunctionToInvokeAndLog in analysis.js. However, you need to be really careful when you modify the function. You should never call push on a ConcolicValue.

[simonhj]

I see. Thanks for the clarification.

[msridhar]

I slightly disagree with the characterization here. This is not a bug, but it's because we do not model the fact that console.log converts its argument to a string. The following example will work:

var x = new Array()
function f() {
    x.push({p: "foo"})
    console.log(String(x))
}
f()

It works by recording the return value of native function String, not by re-constituting the array. While console is not part of any standard specification, at some point we may want to model its behavior more accurately to avoid confusion; I'll open a separate issue.