Can't inject services which extend RepositoryService

I tried to implement a custom validator with class-validator https://github.com/typestack/class-validator#custom-validation-classes. I used the example project from this repository.

I added the following class:

import { ValidatorConstraint, ValidatorConstraintInterface } from 'class-validator';
import { Injectable } from '@nestjs/common';
import { UsersService } from './users.service';

@ValidatorConstraint({ name: 'doesUserAlreadyExist', async: true })
@Injectable()
export class DoesUserAlreadyExist implements ValidatorConstraintInterface {
  constructor(private usersService: UsersService) {}

  async validate(text: string) {
    const users = await this.usersService.getMany({
        filter: [
            {
                field: 'email',
                operator: 'eq',
                value: text
            }
        ]
    });
    return users.length === 0 ? true : false;
  }
}

And added the validator to the User class (Entity):

...
  @Validate(DoesUserAlreadyExist, {
    message: 'User already exists',
  })
  @Column({ type: 'varchar', length: 255, nullable: false, unique: true })
  email: string;
...

I get the following error:

/Users/kai/Development/NodeJS/crud/integration/typeorm/node_modules/@nestjs/typeorm/dist/common/typeorm.utils.js:8
    return `${entity.name}Repository`;
                     ^
TypeError: Cannot read property 'name' of undefined
    at Object.getRepositoryToken (/Users/kai/Development/NodeJS/crud/integration/typeorm/node_modules/@nestjs/typeorm/dist/common/typeorm.utils.js:8:22)
    at Object.exports.InjectRepository (/Users/kai/Development/NodeJS/crud/integration/typeorm/node_modules/@nestjs/typeorm/dist/common/typeorm.decorators.js:5:72)
    at Object.<anonymous> (/Users/kai/Development/NodeJS/crud/integration/typeorm/src/users/users.service.ts:12:16)
    at Module._compile (internal/modules/cjs/loader.js:738:30)
    at Module.m._compile (/Users/kai/Development/NodeJS/crud/integration/typeorm/node_modules/ts-node/src/index.ts:439:23)
    at Module._extensions..js (internal/modules/cjs/loader.js:749:10)
    at Object.require.extensions.(anonymous function) [as .ts] (/Users/kai/Development/NodeJS/crud/integration/typeorm/node_modules/ts-node/src/index.ts:442:12)
    at Module.load (internal/modules/cjs/loader.js:630:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:570:12)
    at Function.Module._load (internal/modules/cjs/loader.js:562:3)

If I remove the injected UsersService dependency injection from the DoesUserAlreadyExist class everything works again. Is it not possible to use the services which extends the RepositoryService service? Or is there another way to execute the repository methods (getMany, getOne, etc.)?

[kairauer]

To anyone else who gets a similar issue, I think this is related to this issue: https://github.com/nestjs/nest/issues/528

[michaelyali]

Yes, that was my point. And, in general, I think it has nothing to do with RepositoryService or with NestJs, but I think it’s a TypeORM issue instead.