Multiple 'You are running Vue in development mode.' & $attrs is readonly. / $listeners is readonly

[ccoplestone]

Hi all,

Odd one here relating to Vue 2, I've had this issue once or twice before and solved it by finding the culprit that was importing the other instance/version of Vue to remove the $attrs/$listeners warnings.

I've since created multiple Docker containers and moved areas of my application into them (frontend/mysql/php) etc, all using nginx. Since then, the 'You are running Vue in development mode.' message is appearing 3 times. Also, the $attrs/$listeners warnings seem to appear on a few different third-party packages, and don't appear on the original setup which leads me to believe this could be an issue with the container (this is isolated to the 'draggable' component, it mentions quite a few on different pages/Vue apps):

Solutions I've tried:

1. Setting an alias for Vue such as:

mix.alias({
    '@': path.join(__dirname, 'resources/js'),
    '~': path.resolve(__dirname, 'resources/sass/'),
    vue$: path.resolve('./node_modules/vue/dist/vue.runtime.esm.js')
})

2. Tried moving the problem third-party packages into their own plugins

3. Tried ssh-ing into the frontend container to see if, at any point, node_modules had been included multiple times causing the issues

4. Tried ensuring node and npm versions are identical to the old environment before I dockerized everything.

The only place I'm importing Vue is in the bootstrap.js file like import Vue from 'vue';. Nowhere else in my codebase am I importing Vue like that, nor am I including it from a CDN.

The docker-compose.yml file for the frontend container:

  frontend:
    container_name: frontend
    build:
      context: .
      dockerfile: ./Dockerfile.dev
      target: frontend
    command:
      - /bin/bash
      - -c
      - |
        npm install
        npm run watch
    volumes:
      - '.:/opt/apps/projectx'
      - '/opt/app/node_modules/'
    networks:
  - testnetwork

Any potential pointers would be greatly appreciated.