Error thrown by INestApplicationContext.select() not caught

[RocheVal]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

When using INestApplicationContext.select to select a module that is NOT loaded in the app an error is thrown (Nest could not select the given module (it does not exist in current context)).
But this error is not caught by try/catch, preventing us to handle the error manually, resulting in crashing the app.

You can see in the stackblitz provided that the console.log located in the main.ts is not triggered when a module is not found.

I have discussed this on discord, and we concluded it might be a bug.

Minimum reproduction code

https://stackblitz.com/edit/nestjs-starter-rgdzro?file=src%2Fmain.ts

Steps to reproduce

In your main.ts:

try {
    app.select(NotLoadedModule);
  } catch (e) {
    console.log('Module not loaded');
  }

Or just run the stackblitz provided.

Expected behavior

I expect the error thrown by the select to be caught by the try/catch.

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

10.2.10

Packages versions

@nestjs/10.2.10

Node.js version

18.16.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

No response

[yannkaiser]

This is due to the exceptionProxy when you call NestFactory.create, see:

nest/packages/core/nest-factory.ts

Line 268 in 180bdf6

const teardown = this.abortOnError === false ? rethrow : undefined;

There is an option you can pass to create to not abort on error, would that be a solution to your issue ?

i.e.:

  const app = await NestFactory.create(AppModule, { abortOnError: false });
  try {
    app.select(NotLoadedModule);
  } catch (e) {
    console.log('Module not loaded');
  }

[RocheVal]

Okay that's why.

I didn't know about abortOnError.
But I would like to keep the abortOnError behavior for the all the other errors.
It's just when selecting a non existing module that I would like to be able to catch and handle the error myself.

To be clear, this problem is not blocking for me (I found some workarounds) but I thought there might be an issue with the select that's why I created this issue.

In my opinion it would be nice to have this behavior, but I let you see if you want to change it or not.
I don't know if it's worth it.

Thanks for your answer !

[micalevisk]

so we have two things here:

1. abortOnError: false will allow us to catch that exception. So what you're reporting is not a bug
2. We'll see the error message on console even when we're handling the exception because of the following line

nest/packages/core/errors/exceptions-zone.ts

Line 17 in 15cb568

this.exceptionHandler.handle(e);

I'm not sure if [2] is a bug, tho.

---

@RocheVal what do you think about introducing a new options arg to app.select so we could supply abortOnError: false to it while keeping the abortOnError: true for the rest?

[RocheVal]

Sorry for the late reply.

@micalevisk introducing this new options seems a good idea to me.
I would be able to handle the presence (or not) of a module in a clean way.

[micalevisk]

@RocheVal please open a feature request issue for that

[RocheVal]

Done #13735