How to solve conflicting members in scala trait (org.slf4j.Logger/com.typesafe.scalalogging.Logger)

Question

I'm using Spark 2.1.1 . This is my problem:

I have 2 files in the same directory named tools. One is main_process.scala and the other one is main_process_fun.scala. The files, basically looks like this:

1.- main_process.scala:

package mod.pack.tools

import x.y.spark.InitSpark
import com.typesafe.config.Config

trait main_process extends InitSpark with main_process_fun {
  this: InitSpark  =>
  /**
    * @param spark  Initialized SparkSession
    * @param config Config retrieved from args
    */
  override def run(spark: SparkSession, config: Config): Int = {
    logger.info("LOG")
    implicit val sparkSes = spark

    pre_defined_f1(config).flatMap(cfg => pre_defined_f2(cfg).flatMap(pre_defined_f3(_, cfg))) match {
      case Success(_) =>
        logger.info("OK")
      case Failure(e) =>
        logger.info("ERROR")
    }
  }
}

2.- main_process_fun.scala:

package mod.pack.tools

import mod.pack.tools.another_folder.another_trait
import com.typesafe.config.Config

trait main_process_fun extends another_trait with com.typesafe.scalalogging.LazyLogging {

  def pre_defined_f1(conf: Config): Try[Config] = Try {
    blablabla
  }

  def pre_defined_f2(conf: Config)(implicit spark: SparkSession): Try[DataFrame] = Try {
    blablabla
    logger.info("LOG")
  }

  def pre_defined_f3(conf: Config): Column = {
    blablabla
    logger.info("LOG")
  }
}

I have an error when trying to compile the project. The error says:

trait main_process inherits conflicting members
lazy value logger in trait LazyLogging of type org.slf4j.Logger and
lazy value logger in trait LazyLogging of type com.typesafe.scalalogging.Logger
(Note: this can be resolved by declaring an override in trait main_process.)
trait main_process extends InitSpark with main_process_fun {

I've already tried to override the logger, but I got this error message:

lazy value logger has incompatible type

I also tried to import main_process_fun instead of extending it from main_process, but without success, I don't know if I did it the wrong way or if the idea itself is bad to solve this issue.

I would greatly appreciate your help to solve this inheritance conflict!

By the way, logger is defined as:

package com.typesafe.scalalogging
trait LazyLogging extends scala.AnyRef {
 @scala.transient
 protected lazy val logger : com.typesafe.scalalogging.Logger = { /* compiled code */ }
}

Answer 1

The error messages explain that there are two versions of logger, one in org.slf4j.Logger and the other in com.typesafe.scalalogging.Logger. These conflict with each other, so you need to drop one. InitSpark appears to use the first of these, so use the same type in the second trait as well:

trait main_process_fun extends another_trait with org.slf4j.Logger {