symfony - Symfony2, composer, your PHP version (5.6.18) overriden by "config.platform.php" version (5.3.9) does not satisfy requirement

Question

I am trying to install doctrine to my project. I am getting the error about the wrong PHP version. What can be done to remove the real reason for this error? The way to overcome it is to use the option "--ignore-platform-reqs" as described https://getcomposer.org/doc/03-cli.md#require .

PHP version: PHP 5.6.18

PHP 5.6.18  (cli) (built: Feb  3 2016 17:20:21)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies

The error: c..>composer require doctrine/data-fixtures

Using version ^1.1 for doctrine/data-fixtures
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - doctrine/migrations v1.3.0 requires php ^5.5|^7.0 -> your PHP version (5.6
.18) overriden by "config.platform.php" version (5.3.9) does not satisfy that re
quirement.
    - doctrine/migrations v1.2.2 requires php >=5.4.0 -> your PHP version (5.6.1
8) overriden by "config.platform.php" version (5.3.9) does not satisfy that requ
irement.
    - doctrine/migrations v1.2.1 requires php >=5.4.0 -> your PHP version (5.6.1
8) overriden by "config.platform.php" version (5.3.9) does not satisfy that requ
irement.
    - doctrine/migrations v1.2.0 requires php >=5.4.0 -> your PHP version (5.6.1
8) overriden by "config.platform.php" version (5.3.9) does not satisfy that requ
irement.
    - doctrine/migrations v1.1.0 requires php >=5.4.0 -> your PHP version (5.6.1
8) overriden by "config.platform.php" version (5.3.9) does not satisfy that requ
irement.
    - doctrine/migrations v1.0.0 requires php >=5.4.0 -> your PHP version (5.6.1
8) overriden by "config.platform.php" version (5.3.9) does not satisfy that requ
irement.
    - Installation request for doctrine/migrations ~1.0 -> satisfiable by doctri
ne/migrations[v1.0.0, v1.1.0, v1.2.0, v1.2.1, v1.2.2, v1.3.0].


Installation failed, reverting ./composer.json to its original content.

The content of composer.json

"require": {
    "php": ">=5.3.9",
    "symfony/symfony": "2.8.*",
    "doctrine/orm": "^2.4.8",
    "doctrine/doctrine-bundle": "~1.4",
    "doctrine/data-fixtures" : "~1.1",
    "doctrine/doctrine-fixtures-bundle": "dev-master",

question from:https://stackoverflow.com/questions/35538071/symfony2-composer-your-php-version-5-6-18-overriden-by-config-platform-php

Answer 1

Somewhere in your composer.json you have

"config": {
   "preferred-install": "dist",
   "platform": {
       "php": "5.3.9"
   }
}

That block overrides your current PHP version as described in composer doc.