Check requirements when running from a PHAR (#116)

An issue one may come across when running a PHAR, as opposed to when you install a tool via Composer, is that no check whatsoever is run.

By leveraging [symfony/requirements-checker](https://github.com/symfony/requirements-checker/), a check is now run when running the PHAR. The check is run _before anything_. The output is the following when checks are passing in very verbose mode (`-vv` or `-vvv`):

![screen shot 2017-10-07 at 12 30 23](https://user-images.githubusercontent.com/5175937/31354701-3cc2cb9c-ad2f-11e7-8787-92c8c9a96b5e.png)

If the very verbose mode is not given, nothing is displayed unless an error occurs. If the checks don't pass, regardless of the verbosity specified, the errors will be printed:

![screen shot 2017-10-07 at 12 28 00](https://user-images.githubusercontent.com/5175937/31354704-3ff9b65e-ad2f-11e7-906c-4dce9104113f.png)

Author: theofidry

.styleci.yml

@@ -11,3 +11,6 @@ disabled:
 finder:
   exclude:
     - 'fixtures'
+  not-path:
+    - 'src/check.php'
+    - 'src/Autoload/Requirements.php'

bin/php-scoper

@@ -2,17 +2,20 @@
 <?php
 
 /*
- * This file is part of the webmozart/php-scoper package.
+ * This file is part of the humbug/php-scoper package.
  *
- * (c) Bernhard Schussek <[email protected]>
+ * Copyright (c) 2017 Théo FIDRY <[email protected]>,
+ *                    Pádraic Brady <[email protected]>
  *
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
 
 namespace Humbug\PhpScoper;
 
-$autoload = (function () {
+use RuntimeException;
+
+$findAutoload = function () {
     if (file_exists($autoload = __DIR__.'/../../../autoload.php')) {
         // Is installed via composer
         return $autoload;
@@ -23,15 +26,51 @@ $autoload = (function () {
         return $autoload;
     }
 
-    return __DIR__.'/../vendor/autoload.php';
-})();
+    if (file_exists($autoload = __DIR__.'/../vendor/autoload.php')) {
+        // Is installed locally
+        return $autoload;
+    }
+
+    throw new RuntimeException('Unable to find the Composer or PHP-Scoper autoloader.');
+};
 
-require_once $autoload;
+$autoload = $findAutoload();
 
+require $autoload;
+
+// Exposes the finder used by PHP-Scoper PHAR to allow its usage in the configuration file.
 if (false === class_exists('Isolated\Symfony\Component\Finder\Finder')) {
     class_alias('Symfony\Component\Finder\Finder', 'Isolated\Symfony\Component\Finder\Finder');
 }
 
+$isVeryVerbose = array_reduce(
+    $argv,
+    /**
+     * @param bool $isVeryVerbose
+     * @param string $param
+     *
+     * @return bool
+     */
+    function ($isVeryVerbose, $arg) {
+        return $isVeryVerbose || '-vv' === $arg || '-vvv' === $arg;
+    },
+    false
+);
+
+if ('phar:' === substr(__FILE__, 0, 5)) {
+    $checkPassed = check_requirements(__DIR__.'/../composer.json', $isVeryVerbose);
+
+    if (false === $checkPassed) {
+        exit(1);
+    }
+}
+
+require __DIR__.'/../src/functions.php';
+
+if (file_exists(__DIR__.'/../tests/functions.php')) {
+    require __DIR__.'/../tests/functions.php';
+}
+
 $app = create_application();
 
 $app->run();

box.json.dist

@@ -16,6 +16,10 @@
                 "vendor-bin"
             ],
             "in": "vendor"
+        },
+        {
+            "name": "composer.json",
+            "in": "."
         }
     ],
     "compression": "GZ",

composer.json

@@ -19,12 +19,14 @@
 
     "require": {
         "php": "^7.1",
+        "composer/semver": "^1.4",
         "nikic/php-parser": "^3.0",
         "ocramius/package-versions": "^1.1",
         "padraic/phar-updater": "^1.0",
         "symfony/console": "^3.2",
         "symfony/filesystem": "^3.2",
-        "symfony/finder": "^3.2"
+        "symfony/finder": "^3.2",
+        "symfony/requirements-checker": "^1.0"
     },
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.1",
@@ -37,16 +39,13 @@
             "Humbug\\PhpScoper\\": "src/"
         },
         "files": [
-            "src/functions.php"
+            "src/check.php"
         ]
     },
     "autoload-dev": {
         "psr-4": {
             "Humbug\\PhpScoper\\": "tests/"
-        },
-        "files": [
-            "tests/functions.php"
-        ]
+        }
     },
 
     "config": {

composer.lock

@@ -11,12 +11,11 @@ file that was distributed with this source code.
 
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.0/phpunit.xsd"
-         backupGlobals="false"
-         bootstrap="vendor/autoload.php"
+         bootstrap="tests/autoload.php"
          colors="true"
 >
     <testsuites>
-        <testsuite name="Webmozart PHP-Scoper Test Suite">
+        <testsuite name="PHP-Scoper Test Suite">
             <directory suffix="Test.php">./tests/</directory>
         </testsuite>
     </testsuites>

phpunit.xml.dist

@@ -0,0 +1,78 @@
+<?php
+
+/*
+ * This file is part of the humbug/php-scoper package.
+ *
+ * Copyright (c) 2017 Théo FIDRY <[email protected]>,
+ *                    Pádraic Brady <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Humbug\PhpScoper\Autoload;
+
+use Composer\Semver\Semver;
+use Symfony\Requirements\RequirementCollection;
+
+/**
+ * Collect the list of requirements for running the project. Code in this file must be PHP 5.3+ compatible as is used
+ * to know if PHP-Scoper can be run or not.
+ */
+final class Requirements extends RequirementCollection
+{
+    public function __construct($composerJson)
+    {
+        $composerConfig = $this->readComposer($composerJson);
+
+        $this->addPhpVersionRequirement($composerConfig);
+        $this->addExtensionRequirements($composerConfig);
+    }
+
+    private function readComposer($composerJson)
+    {
+        $composer = json_decode(file_get_contents($composerJson), true);
+
+        return $composer['require'];
+    }
+
+    private function addPhpVersionRequirement(array $composerConfig)
+    {
+        $installedPhpVersion = phpversion();
+        $requiredPhpVersion = $composerConfig['php'];
+
+        $this->addRequirement(
+            Semver::satisfies(phpversion(), $requiredPhpVersion),
+            sprintf(
+                'PHP version must satisfies "%s" ("%s" installed)',
+                $requiredPhpVersion,
+                $installedPhpVersion
+            ),
+            ''
+        );
+    }
+
+    private function addExtensionRequirements(array $composerConfig)
+    {
+        foreach ($composerConfig as $package => $constraint) {
+            if (preg_match('/^ext-(?<extension>.+)$/', $package, $matches)) {
+                $this->addExtensionRequirement($matches['extension']);
+            }
+        }
+    }
+
+    /**
+     * @param string $extension Extension name, e.g. `iconv`.
+     */
+    private function addExtensionRequirement($extension)
+    {
+        $this->addRequirement(
+            extension_loaded($extension),
+            sprintf(
+                'The extension "%s" must be enabled.',
+                $extension
+            ),
+            ''
+        );
+    }
+}