For some database schemas, PgIntrospectionPlugin.js abruptly crashes NodeJS (with --track-heap-objects flag, or memory profiling) about graphile-engine

[Venryx]

I just tested it, and yes, that unrolled version also resolves the crash. :) (And yeah, it definitely seems like a better fix, since it avoids the redundant function declaration.)

On my end, I'm still waiting for the NodeJS dev team to see what they have to say on the crash. (ie. whether they plan to fix it, or if it's enough of an edge-case that it's deprioritized/forgotten-about)

[Venryx]

Closing the issue, since I'm assuming the NodeJS team will fix the root problem. (if not, it can be re-opened)

[Venryx]

I have found a workaround for the bug for now, involving a slight refactor of the deepClone function. See here for details: nodejs/node#41539 (comment)

If the NodeJS devs take too long to fix the root problem, it may be worth creating a pull-request including the slight fix/refactor, since the bug occurs "in the wild" for some schemas supplied to Postgraphile. (and the crash is very hard to debug for people if they don't already know the cause)

[benjie]

I can easily imagine wanting to refactor the workaround to be the non-workaround'd code to avoid the extra function declaration... Maybe we could refactor to use a loop instead - does that still resolve the issue?

const deepClone = value=>{
	if (Array.isArray(value)) {
		const l = value.length;
		const cloned = new Array(l);
		for (let i = 0; i < l; i++) {
			cloned[i] = deepClone(value[i]);
		}
		return cloned;
	}
	if (typeof value === "object" && value) {
		// Unrolled `reduce` to work around memory bug in Node.js
		const cloned = Object.create(null);
		const keys = Object.keys(value);
		for (let i = 0, l = keys.length; i < l; i++) {
			const k = keys[i];
			cloned[k] = deepClone(value[k]);
		}
        return cloned;
	}
	return value;
};

[benjie]

I'm going to close this again, because yes I think it's Node.js' responsibility to fix this.