DI issue - Injectable extending Injectable

[ghost]

Hey guys,

We have around 60 dynamic modules imported into root module. These modules share most of the common behaviour / services, but few of them would like to do some overrides / customisation of common behaviour / services.

We've done it in a way where each of these dynamic modules creates own instances of common services (has it in providers), and whichever module would like to change common behaviour would extend the base service, and provide it like { provider: SomeService, useClass: MyCustomService } where MyCustomService extends SomeService. We've encountered an issue with injecting dependencies into constructors of these classes.

Actual reasoning behind this approach is quite complex, but pls check short example below.

[ ] Regression 
[ x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

Both modules below are imported into one root module.

@Injectable()
export class Service {
  constructor (@Inject('Value1') value: number) {
    console.log(`Service1 -> ${value}`)
  }
}

@Injectable()
export class ServiceCustom extends Service {
  constructor (@Inject('Value2') value: number) {
    super(value)
    console.log(`Service2 -> ${value}`)
  }
}

@Module({
  providers: [
    { provide: 'Value1', useValue: 1 },
    { provide: 'Value2', useValue: 2 },
    Service
  ]
})
export class ModuleWithBaseServiceBehaviour {
}

@Module({
  providers: [
    { provide: 'Value1', useValue: 1 },
    { provide: 'Value2', useValue: 2 },
    { provide: Service, useClass: ServiceCustom }
  ]
})
export class ModuleThatOverridesBaseServiceBehaviour {
}

Both Service and ServiceCustom got injected value 2, so dependencies from Service were injected in to ServiceCustom.

Expected behavior

If I am extending an injectable class and providing this custom class in different module under same injection token, I would expect that both constructors have dependecies injected correctly.

Minimal reproduction of the problem with instructions

see example above

Environment

Nest version: 5.4.0
 
For Tooling issues:
- Node version: 10.6.0
- Platform:  Mac

[kamilmysliwiec]

So what is the output of this code snippet:

@Injectable()
export class Service {
  constructor (@Inject('Value1') value: number) {
    console.log(`Service1 -> ${value}`)
  }
}

@Injectable()
export class ServiceCustom extends Service {
  constructor (@Inject('Value2') value: number) {
    super(value)
    console.log(`Service2 -> ${value}`)
  }
}

This explanation:

Both Service and ServiceCustom got injected value 2, so dependencies from Service were injected in to ServiceCustom.

is not clear enough, since "2" value = Value2, not Value1

[ghost]

Hi Kamil,

sry that console.log might be bit misleading there as Service ctor gets also called in ServiceCustom ctor.

Anyways there should be one output line Service1 -> 1, but there is not.

Issue is that with this setup, instance of Service in first module get injected what CustomService from second modules has declared in its ctor arguments. Service gets inejcted completely wrong instances.
In our use cases it meant e.g. I did @Inject(LOGGER) and got instance of completely different thing...

[kamilmysliwiec]

Are you able to create a small reproduction repository? It would help a lot

[ghost]

Pls check here:
https://github.com/jurajsipos/nest-di-issue

[ghost]

More understandable example here as it cannot resolve Service dependencies, even though it should.

@Injectable()
export class Service {
  constructor (@Inject('Value1') value: number) {
  }
}

@Injectable()
export class ServiceCustom extends Service {
  constructor (@Inject('Value2') value: number) {
    super(value)
  }
}

@Module({
  providers: [
    { provide: 'Value1', useValue: 1 },
    Service
  ]
})
export class ModuleWithBaseServiceBehaviour {
}

@Module({
  providers: [
    { provide: 'Value2', useValue: 2 },
    { provide: Service, useClass: ServiceCustom }
  ]
})
export class ModuleThatOverridesBaseServiceBehaviour {
}

@Module({
  imports: [
    ModuleWithBaseServiceBehaviour,
    ModuleThatOverridesBaseServiceBehaviour
  ]
})
export class AppModule {
}

Nest can't resolve dependencies of the Service (?). Please make sure that the argument at index [0] is available in the ModuleWithBaseServiceBehaviour context.

[kamilmysliwiec]

Fixed by #1345, thanks for reporting!

[kamilmysliwiec]

Fixed in 5.5.0 :)

[lock]

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