including dependency in magento

Question

I was trying to publish one extension to magento marketplace

Things are a fork of tinypng and I can see the dependency of tinypng module is automatically pulled by composer, but where they are putting those dependency?

When you download their Magento plugin, you cant find dependency in that folder, but when you install it, you can see tinify folder under vendor folder of root directory. Here is tinypng composer.json

I think composer is pulling this folder but how? It is not absolute link and I cant find any way to include our dependency similar to tinypng. Any help will be great.

tinify/tinify:

{
  "name": "tinify/magento2",
  "type": "magento2-module",
  "version": "1.1.1",
  "description": "Make your web shop faster by compressing your JPEG and PNG images. This plugin automatically optimizes your images by integrating with the popular image compression services TinyJPG and TinyPNG.",
  "keywords": [
    "tinify",
    "tinypng",
    "tinyjpg",
    "compress",
    "images",
    "api",
    "magento",
    "magento2",
    "plugin",
    "module"
  ],

  "homepage": "https://tinify.com/developers",
  "license": "MIT",

  "support": {
    "email": "[email protected]"
  },

  "authors": [{
    "name": "Rolf Timmermans",
    "email": "[email protected]"
  }],

  "minimum-stability": "alpha",
  "require": {
    "php": ">=5.5.0",
    "ext-curl": "*",
    "ext-json": "*",
    "tinify/tinify": ">=1.5"
  },

  "require-dev": {
    "phpunit/phpunit": "~4.0",
    "mikey179/vfsstream": "~1",
    "squizlabs/php_codesniffer": "~2.0",
    "codeception/aspect-mock": "*"
  },

  "autoload": {
    "files": ["registration.php"],
    "psr-4": {"Tinify\\Magento\\": "src"}
  }
}

Answer 1

in composer, you can have dependencies of dependencies (and so on) which can make it really difficult, to figure out, why this dependency is installed.

But, if it is installed via composer, there is a command, to figure out, which module requires it:

composer why tinify/magento2