Nestjs controller vs forwardRef issue

[unborn grail]

Is there an existing issue for this?
I have searched the existing issues
Current behavior
This issue will happen with the bellow condition

The controller inject service A
Service A has using forwardRef for inject service B
Service A constructor call the async function for modified the service A property
=> From the controller, we can't access the latest value of that property. The value has been cached.
Minimum reproduction code
https://github.com/khanhx/nestjs-controller-forwardref-bug

Steps to reproduce
npm ci
npm run start
image
Expected behavior
The value from controller should match with value in the service A since we only have one instance of service A

Package
I don't know. Or some 3rd-party package
@nestjs/common
@nestjs/core
@nestjs/microservices
@nestjs/platform-express
@nestjs/platform-fastify
@nestjs/platform-socket.io
@nestjs/platform-ws
@nestjs/testing
@nestjs/websockets
Other (see below)
Other package
No response

NestJS version
No response

Packages versions
"@nestjs/common": "^10.3.2",
"@nestjs/core": "^10.3.2",
"@nestjs/platform-express": "^10.3.2",
"reflect-metadata": "^0.2.1",
"rxjs": "^7.8.1"
Node.js version
v18.18.2

In which operating systems have you tested?
macOS
Windows
Linux
Other
No response

https://github.com/nestjs/nest/issues/13826

Can anyone help me with this, It seem to be not related to any problem before. The code working as we have 2 instance of service but the constructor only call once

[flat onyx]

This seems strange to me. Does it work correctly when you remove the forward ref?

If you haven't solved it yet, I'll try to run your repro when I have time

[flat onyx]

I also couldn't find any issue where this was discussed in the past like Kamil said 🤷‍♂️

[solemn marsh]

Your code doesn't make any sense...
You re-assign the instanceKey value and log it to the console at the random states of lifecycle...

1. First of all kicks you AppService at the line 9 with your first value assign instanceKey = Math.random(); on module init... Which then you log it inside constructor line 11
2. Then your constructor execut this code

    setTimeout(() => {
      console.log(333333, 'AppService current value', this.instanceKey);
    }, 3000);
    this.init();

Which first you see the this.init(); value that you re-assign on line 21 this.instanceKey = Math.random(); with the new value.

And you see it first sinse your setTimeout function set to 1 second.
Then you see the first part of your constructor:

    setTimeout(() => {
      console.log(333333, 'AppService current value', this.instanceKey);
    }, 3000);

Because you set it to 3 seconds later with the same value from line 21 (check out the sreenshot)

3. Finally you controller kicks in

  constructor(
    @Inject(forwardRef(() => AppService))
    private appService: AppService,
  ) {
    setTimeout(() => {
      console.log(11111, 'AppController current value', this.appService?.instanceKey);
    }, 3000);
  }

with delay of 3 seconds after private appService: AppService, initialized and constructor executed.

Basically nothing in your code is "async", especially the constructor that cannot be async.

So everything work as expected.

Under the hood, when you use setTimeout function, nothing is going to nodejs libuv (the library that makes your code async), you push the values (the callbacks) to event-loop in sorted order by time. Then the event-loop execute it one-by-one.

[flat onyx]

If I'm not completely mistaken, the callback passed to setTimeout should execute after the timeout has passed, which means the variable should be read 2 seconds after it had been changed (which is 1 second after init), so we should see the new value in the constructor. But we don't.