Nest.js无参数方法调用失败问题排查与解决

问题现象 #

以下控制器方法可正常运行：

@ApiOkResponse({
    type: Bird,
  })
  @Get('demoBird')
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  async demo(@Query('dummy') _dummy: string) {
    this.logger.log('findDemoBird');
    return this.service.findDemoBird();
  }

但移除其中的@Query('dummy') _dummy: string参数声明后，调用接口会抛出如下错误：

error Application: Cannot read properties of undefined (reading 'findDemoBird')

项目中其他控制器的无参数方法均可正常执行，核心依赖版本如下：

"@nestjs/core": "^9.0.0",
 "ts-jest": "28.0.8",
 "ts-loader": "^9.2.3",
 "ts-node": "^10.0.0",
 "tsconfig-paths": "4.1.0",
 "typescript": "^4.7.4"

控制器完整代码 #

import {
  Body,
  Controller,
  Delete,
  Get,
  Inject,
  Param,
  Patch,
  Post,
  Put,
  Query,
} from '@nestjs/common';
import { UpdateBirdDto } from './dtos/update-bird.dto';
import { BirdService } from './bird.service';
import { TraceableLogger } from 'src/common/logger/TraceableLogger';
import { Bird } from './bird.schema';
import {
  ApiTags,
  ApiOperation,
  ApiParam,
  ApiOkResponse,
  ApiExtraModels,
  ApiNotFoundResponse,
  ApiInternalServerErrorResponse,
  getSchemaPath,
  ApiQuery,
  ApiBody,
} from '@nestjs/swagger';
import { Subscription } from 'src/billing/subscription/subscription.schema';
import { UpdateLoansGdprDto } from '../loan/dtos/update-loans-gdpr.dto';

@Controller('birds')
export class BirdController {
  constructor(
    @Inject('BirdLogger') private readonly logger: TraceableLogger,
    private readonly service: BirdService,
  ) {
    this.logger.setContext(BirdController.name);
  }
}

解决方案 #

注释掉BirdService构造函数中的@Inject(forwardRef(() => SubscriptionService))装饰器后，问题得到解决：

@Injectable()
export class BirdService {
  constructor(
    private readonly repository: BirdRepository,
    //// @Inject(forwardRef(() => SubscriptionService))
    private readonly subscriptionService: SubscriptionService,
    private readonly autoService: CarService,
    private readonly katzenService: CatService,
    @Inject('BirdLogger') private readonly logger: TraceableLogger,
  ) {
    this.logger.setContext(PracticeService.name);
  }
}

补充SubscriptionService构造代码 #

@Injectable()
export class SubscriptionService {
  private schemaFields: string;
  private readonly logger = new Logger(SubscriptionService.name);

  constructor(
    @InjectModel(Subscription.name, 'birds')
    private readonly model: Model<Subscription>,
    private readonly configService: ConfigService,
  ) {
    this.schemaFields = Object.keys(SubscriptionSchema.paths).join(' ');
  }
}

内容的提问来源于stack exchange，提问作者DraganS