Getting Installation request errors from composer when trying to create a sylius project?

Question

When I try to perform:

composer create-project -s dev sylius/sylius:dev-master

I receive the following error:

Installing sylius/sylius (dev-master 0da3c0022d3118135e56908dfa4c69e6699770ce)
  - Installing sylius/sylius (dev-master master)
    Cloning master

Created project in sylius
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for fabpot/goutte v1.0.3 -> satisfiable by fabpot/goutte[v1.0.3].
    - fabpot/goutte v1.0.3 requires ext-curl * -> the requested PHP extension curl is missing from your system.
  Problem 2
    - Installation request for instaclick/php-webdriver 1.0.17 -> satisfiable by instaclick/php-webdriver[1.0.17].
    - instaclick/php-webdriver 1.0.17 requires ext-curl * -> the requested PHP extension curl is missing from your system.
  Problem 3
    - fabpot/goutte v1.0.3 requires ext-curl * -> the requested PHP extension curl is missing from your system.
    - behat/mink-goutte-driver v1.0.9 requires fabpot/goutte ~1.0.1 -> satisfiable by fabpot/goutte[v1.0.3].
    - Installation request for behat/mink-goutte-driver v1.0.9 -> satisfiable by behat/mink-goutte-driver[v1.0.9].

Answer 1

This error occurs when you are missing the PHP curl extensions. Some of the sylius dependencies are dependent on that extension.

To solve this error just install and enable the php-curl extension.

With apt-get:

sudo apt-get install php5-curl

Or follow:

http://php.net/manual/en/curl.installation.php

Answer 2

Add minimum-stability option to composer.json file.

{
    "require": {
        "php-ews/php-ews": "dev-master"
    },
    "minimum-stability": "dev"
}