Object formating is limitless => Problems with giantic arrays

[Phaiax]

Hey

Using Sinon.JS asertions in browser mode with html formating and a failed assertion (eg calledTwice) causes Sinon to format (to string) all calls to the spied function. Thereby all objects will be formated recoursively. The formater prevents formations of already formated objects -> [circular reference], but it does not prevent the stringification of big arrays.

I'm using Phaser, a game framework. It has an internal array for the Canvas it's painting on. This Uint8ClampedArray has a default size of 1024 * 1024 * 4 = 4194304. I don't know if it's the only array, but the stringification of the array(s) takes more than 1GB of RAM and causes the script to "not respond".

You can't blame a lib to use large arrays, so Sinon.JS must handle this.

Simple example using Phaser to trigger the problem. It will also work if you just create a big array and try to format it:

var g = new Phaser.Game(400, 400, Phaser.AUTO, null, null); // only needed because BitmapData needs a Game Object
var o = {s : new Phaser.BitmapData(g, '__root', 1024, 1024)} ;

sinon.format(o);

I'll create a patch and attach it to this issue. I think arrays and object should have a maximum of 100..150 formated properties,

[Phaiax]

Ok, after a little bit of investigation i found, that sinon is using formatio for formating.

https://github.com/busterjs/formatio

Like sinon does with

    var formatter = formatio.configure({ quoteStrings: false });

you can configure formatio to behave special.
The cleanest solution would be to add a new config for the maximum array length to formatio and set it properly in sinon.

[Phaiax]

I created a patch for formatio, and I saw that you (@cjohansen) are also a maintainer of formatio, so it will be easy for you to merge my patch (if it's acceptable :).

Sinon.JS is missing the config, but it's just replacing

{ quoteStrings: false }
with
{ quoteStrings: false, limitChildrenCount: 250 }
in sinon.js line 366

Hope you'll fix this, thank you and kind regards
Phaiax

[mroderick]

Hmm, this shouldn't be closed yet. We still need to use a new formatio version

[cjohansen]

Oops, sorry!