Async Derive leaks request context to other requests if aot:true

[Mkassabov]

What version of Elysia.JS is running?

0.8.16

What platform is your computer?

Microsoft Windows NT 10.0.22621.0 x64

What steps can reproduce the bug?

have an async derive hook in an elysia instance with aot: false;

What is the expected behavior?

async derive in aot:false environment should not leak contexts between requests

What do you see instead?

context from newer requests leaks into the handlers of old requests

Additional information

reproduction code:

import { Elysia } from "elysia";

const app = new Elysia({ aot: false })
	.derive(() => new Promise((resolve) => setTimeout(resolve, 1000)))
	.get("/test", ({ request }) => {
		console.log(request.url);
	});

app.handle(new Request("http://localhost:1025/test"));
app.handle(new Request("http://localhost:1025/bad"));

the above code, when run, logs http://localhost:1025/bad, expected behavior is to log http://localhost:1025/test;

[Mkassabov]

worth noting this also extends to request validation, etc. It seems the context of the new request just entirely replaces the context of the old request.

[SaltyAom]

Fixed on #465, waiting for merge.

[MatthewAry]

When using derive .derive(async () => {}) as in this contrived example, I get a TS error Type 'Promise<void>' is not assignable to type 'Record<string, unknown>. It seems there is a problem with signature of the return type for derive which is breaking the MaybePromise part of the return type.

[Mkassabov]

When using derive .derive(async () => {}) as in this contrived example, I get a TS error Type 'Promise<void>' is not assignable to type 'Record<string, unknown>. It seems there is a problem with signature of the return type for derive which is breaking the MaybePromise part of the return type.

I originally ran into this when it was an async function that returned a Record<string, unknown>. I just tried to find the most minimal repro possible to demonstrate its a problem. it probably would've been better to have the set timeout use () => resolve({}) instead of just resolve

[MatthewAry]

Circling back to this, the issue I ran into is present on 1.0.0-beta.2 I don't think it's fixed on #465

[Mkassabov]

@MatthewAry

Circling back to this, the issue I ran into is present on 1.0.0-beta.2 I don't think it's fixed on #465

do you have a repro for this? the reproduction above works fine in 1.0.0-beta.2

[MatthewAry]

I currently do not have a sharable reproduction, but I have definitely tracked down the issue.

So the built version of Elysia 1.0.0-beta.2 has a file elysia/dist/dynamic-handle-UZxzFa2z.d.ts which gives derive a definition of

    derive<const Derivative extends Record<string, unknown>>(transform: (context: Prettify<Context<Metadata['schema'], Singleton>>) => MaybePromise<Derivative> extends {
        store: any;
    } ? never : Derivative): Elysia<BasePath, Scoped, {
        decorator: Singleton['decorator'];
        store: Singleton['store'];
        derive: Prettify<Singleton['derive'] & Awaited<Derivative>>;
        resolve: Singleton['resolve'];
    }, Definitions, Metadata>;

It's being set here

elysia/src/index.ts

Lines 4497 to 4519 in ff5d5ac

	derive<const Derivative extends Record<string, unknown>>(
	transform: (
	context: Prettify<Context<Metadata['schema'], Singleton>>
	) => MaybePromise<Derivative> extends { store: any }
	? never
	: Derivative
	): Elysia<
	BasePath,
	Scoped,
	{
	decorator: Singleton['decorator']
	store: Singleton['store']
	derive: Prettify<Singleton['derive'] & Awaited<Derivative>>
	resolve: Singleton['resolve']
	},
	Definitions,
	Metadata
	> {
	// @ts-ignore
	transform.$elysia = 'derive'
	return this.onTransform(transform as any) as any
	}

and I've determined that my error is coming from the ternary in the callback's return type for derive which is MaybePromise<Derivative> extends { store: any } ? never : Derivative.

Note that the Derivative type is defined as Record<string, unknown> and because the TS Ternary condition can't evaluate to true with something as simple as derive(async () => {}), I can get my error.

I made a PR to fix the issue #484 which gets rid of the ternary, I'm not really sure what it's purpose was to begin with but I could be missing something since I'm not as familiar with the codebase as @SaltyAom or other contributors.

[MatthewAry]

I've updated my PR. #488

[SaltyAom]

Merged #488.

If resolved, please leave the issue opened until release on next stable release.

[SaltyAom]

Should be fixed in 1.0.0

Feels free to reopen if issue still persists.