Calling function returned from complex object

[janober]

Hello,

sadly have one last problem for which I can not figure out what is going on. Would be amazing if you could help me with finding a solution. Thanks a lot for your help!

Here is the code to easily reproduce the issue I am facing:

const { python, builtins } = require('pythonia');

async function main() {
	const proxy = {
		getValue: (parameter1) => {
			return new Proxy(
				{},
				{
					ownKeys(target) {
						return ['first', 'second'];
					},
					getOwnPropertyDescriptor(k) {
						return {
							enumerable: true,
							configurable: true,
						};
					},
					get(target, property, receiver) {
						if (property === 'first') {
							return 'VALUE-first';
						}
						if (property === 'second') {
							return () => {
								return 'VALUE-second';
							};
						}
						return Reflect.get(target, property, receiver);
					},
				},
			);
		},
	};

	await builtins.exec("print(proxy['getValue']('some-key').first)", {
		proxy,
	});
	// Returns as expected:
	//     VALUE-first

	await builtins.exec("print(proxy['getValue']('some-key').second)", {
		proxy,
	});
	// Returns as expected:
	//     [Function (anonymous)]

	await builtins.exec("print(proxy['getValue']('some-key').second())", {
		proxy,
	});
	// Expected:
	//     VALUE-second
	// Actual response:
	//     ERROR
	//     Python Error  Call to 'exec' failed:
	//         await builtins.exec("print(proxy['getValue']('some-key').second())", {
	//      at async main (/data/n8n-python/packages/nodes-base/nodes/PythonFunction/test-node-reference-issue-post.js:44:2)
	// ...     across the bridge ...
}
main().then(() => python.exit());

[janober]

@extremeheat any idea what could be done to make it work?

[extremeheat]

Looked into this and it relates to GC. Python freeing memory after __free__ is called on python-side proxy object, causing JS to free it and resulting in an attempt to call an undefined/deallocated function.

[js -> py] { r: 13, key: 'obj', val: 10004 }
[py -> js] { r: 15, action: 'get', ffid: 10004, key: 'second', c: 'jsi' }
[js -> py] { r: 15, key: 'fn', val: 10005 }
[py -> js] { r: 16, action: 'free', args: [ 10004 ], c: 'jsi' }
[py -> js] {
  r: 17,
  c: 'jsi',
  p: 1,
  action: 'call',
  ffid: 10004,
  key: 'second',
  args: []
}

Seems like __del__ is called before __call__ in

JSPyBridge/src/pythonia/proxy.py

Line 226 in 7879bda

self._exe.free(self.ffid)

which is causing this. Will need further investigation.

[janober]

Thanks a lot for looking into this! So seems like it will not be as "easy" as the other issues I had. I will then have to look for some kind of workaround.
Have a great weekend!