dynamic Modules metadata does not support circular structures

I’m submitting a…

[ ] Regression 
[X] Bug report
[ ] Feature request
[ ] Documentation issue or request

Current behavior

[Nest] 2998   - 2018-5-13 19:41:01   [ExceptionHandler] Converting circular structure to JSON
TypeError: Converting circular structure to JSON
    at JSON.stringify (<anonymous>)
    at ModuleTokenFactory.getDynamicMetadataToken (/home/nest/uroboros/node_modules/@nestjs/core/injector/module-token-factory.js:16:45)
    at ModuleTokenFactory.create (/home/nest/uroboros/node_modules/@nestjs/core/injector/module-token-factory.js:10:27)
    at ModuleCompiler.compile (/home/nest/uroboros/node_modules/@nestjs/core/injector/compiler.js:19:47)
    at NestContainer.addModule (/home/nest/uroboros/node_modules/@nestjs/core/injector/container.js:31:70)
    at DependenciesScanner.storeModule (/home/nest/uroboros/node_modules/@nestjs/core/scanner.js:32:24)
    at DependenciesScanner.scanForModules (/home/nest/uroboros/node_modules/@nestjs/core/scanner.js:22:14)
    at modules.map.innerModule (/home/nest/uroboros/node_modules/@nestjs/core/scanner.js:25:18)
    at Array.map (<anonymous>)
    at DependenciesScanner.scanForModules (/home/nest/uroboros/node_modules/@nestjs/core/scanner.js:24:17)

Expected behavior

Nest application successfully started

Minimal reproduction of the problem with instructions

import { DynamicModule, Module } from '@nestjs/common';

@Module({})
export class UroburosModule {

  static forRoot(): DynamicModule {
    let oyra = {bora:{}};
    const UroburosProvider = {
      name: 'UROBUROS_PROVIDER',
      provide: 'UROBUROS_PROVIDER',
      useValue: oyra.bora = oyra
    };

    return {
      module: UroburosModule,
      providers: [UroburosProvider],
      exports: [UroburosProvider]
    };
  }

}

What is the motivation / use case for changing the behavior?

Allow use of external libraries that contain circular references

Environment

Nest version: 5.0.0

 
For Tooling issues:
- Node version: 10.0.0
- Platform:  Linux

[BrunnerLivio]

Currently trying to upgrade my Nest 4.x.x application to 5.3.10.

My application does have a circular dynamic module and works perfectly fine with 4.x.x, but I’m having the error message TypeError: Converting circular structure to JSON

Looking through your commit history, the commit which fixed this issue is more or less reverted by commit ce498e86150f7de4a260f0c393d47ec4cc920ea1.

Why is this? Can not find any statement on this.

[kamilmysliwiec]

Fixed in v5.0.1