Old SWF file not running (AS2)

[ErdincBARUT]

Describe the bug

Working on Flash Player not working on Ruffle DEMO page.
confeti.zip

Expected behavior

Not running.

Affected platform

Online demo

Operating system

Chrome

Browser

No response

Additional information

confeti.zip

[Toad06]

Thank you for the report.

Ruffle doesn't return the expected value for this in the following line:
eval("this.caida_mc.conf" + confCount).serConfeti();

Replacing this with _root makes the file work in Ruffle (and still works in Flash Player). Here's the edited file.

eval("_root.caida_mc.conf" + confCount).serConfeti();

---

I made a minimal test that reproduces the issue (SWF available here):

this.createEmptyMovieClip("mc", 1);
this.mc.onEnterFrame = function() {
   trace(this); // "_level0.mc" in FP and Ruffle (note: P-code is "Push register1")
   var v = "";

   var a = eval("this" + v); // note: "Push 'this' GetVariable" would produce the same result
   trace(a); // "_level0" in FP, "[type Object]" in Ruffle
   trace(a == _global); // "false" in FP, "true" in Ruffle

   trace("");

   var a = eval("this.mc" + v);
   trace(a); // "_level0.mc" in FP, "undefined" in Ruffle

   delete this.onEnterFrame;
};

Note that before #7239, eval("this" + v) traced _level0.mc (which was also incorrect).

@moulins, as the author of #7239, I think you could have an idea of why this issue is happening.

[ErdincBARUT]

Its not my codes, I tested old swf files and see this problem. I hope Ruffle development gone more faster to complete.
Thank you

[Toad06]

Thanks for reporting it, we'll do our best to fix the issue affecting the original file, so let's keep this bug report open.

[moulins]

It seems that our logic for "inheriting" this when no this local exist is wrong: we pick the this value of the parent activation, which doesn't actually match the lexical scope if the function is executed via the MovieClip's timeline.

I think the "most correct" way of fixing this would to remove the this special case and put this on the scope chain like any other local variable.