Since version 0.9.0, I've encountered an issue with circular references when compiling JavaScript code.

[mengbai123]

Since version 0.9.0, I've encountered issues with errors related to circular references after compiling JavaScript code.

My program supports running JavaScript code after it's compiled into binary files. I modified the output_object_code function in qjsc.c to sequentially output the length and content of each compiled file into a single file. When running the script code, it parses this binary file and repeatedly executes the process of "reading the length -> loading the code" until all the code has been loaded (using js_std_eval_binary to run).

For a long time, this program was able to execute the code correctly, regardless of whether the JavaScript code was compiled or not.

However, starting from version 0.9.0, it has stopped working properly. I've been making efforts to upgrade the version, but I've run into some problems. It's likely that circular references between different JavaScript files after compilation are causing the loading to fail.

// b.js
import {C} from "./c";

function test1() {
    let a = C
}

export function test2() {
    print("test2")
}

// c.js
import {test2} from "./b";

export const C = "CCCCC";

export function test3() {
    test2()
}

// main.js
import {test3} from "./c";

globalThis.main = (args) => {
    test3()
}

The above code could execute correctly both in the JavaScript source code form and after compilation in version 0.8.0.
However, on the latest version of QuickJS, the source code can run normally, but it fails to execute after compilation, with an error message saying "could not load module filename 'c'".

I suspect the problem might be related to circular loading. In the above code, b.js references the constant C from c.js, and c.js references the test2 function from b.js.

But why does it work fine when running the source code and also worked fine in the previous version?

Can someone answer my questions?

[bnoordhuis]

I suppose my first question would be: does it work without your modifications to qjsc? Maybe your changes or your loader has a bug that worked by accident with the bytecode in 0.8.0 but stopped working with the newer bytecode format.

[mengbai123]

https://github.com/mengbai123/quickjs-ng

I forked the quickjs and made minimal modifications to the original code to reproduce my issue.
I modified qjsc.c and qjs.c to enable the compilation and execution of binary code.

I also added a mytest directory containing test code and .bat scripts.

Here are my test results:
With circular references in JS files
JS source code correct
Compiled JS code failed

Without circular references (remove import in b.js)
JS source code correct
Compiled JS code correct

I'm confused and not sure if there's an issue with how I'm loading the code,
but I've confirmed this started happening from version 0.9.0.
It might be related to the underlying promise mechanism.
Could you please help take a look? Thank you!

[bnoordhuis]

I don't see anything obviously wrong. Maybe try git bisect and see what change between 0.8 and 0.9 is responsible.