fix symfony-autocomplete composer vendor

bin/symfony-autocomplete did not honor COMPOSER_VENDOR_DIR and treated it
as if it is the default value "vendor" only.

however it is part of the composer install protocol and required for
the bin-stubs autoloading.  it should not be hard-encoded to the default
value only.

fix is to use COMPOSER_VENDOR_DIR as absolute path, as relative path to
PWD and as relative path to bin/symfony-autocomplete given the first
attempt to try requiring from __DIR__.'/../../../autoload.php' failed.

NOTE: use of include_once instead of require_once is intended here, the EA
      inspection is misleading on it as _once was and still is intended.

this is similar for "acme" in tests, but with the difference that during
build time we insist to know that COMPOSER_VENDOR_DIR is always relative
to the project root, YMMV.

report: #76

Author: ktomk

bin/symfony-autocomplete

@@ -6,11 +6,27 @@ if (function_exists('ini_set')) {
     ini_set('display_errors', 'stderr');
 }
 
-if (file_exists($autoload = __DIR__.'/../../../autoload.php')) {
-    require_once $autoload;
-} else {
-    require_once __DIR__.'/../vendor/autoload.php';
-}
+(/* require vendor autoload file (Composer) */ static function () {
+    $includeIfExists = static function ($file) {
+        /** @noinspection UsingInclusionOnceReturnValueInspection intended */
+        return file_exists($file) ? include_once($file) : false;
+    };
+    if ((!$includeIfExists(
+                __DIR__ . '/../../../autoload.php'
+            ) &&
+            empty($_SERVER['COMPOSER_VENDOR_DIR'])) ||
+        (!$includeIfExists(
+                $_SERVER['COMPOSER_VENDOR_DIR'] . '/autoload.php'
+            ) &&
+            !$includeIfExists(
+                __DIR__ . '/../' . $_SERVER['COMPOSER_VENDOR_DIR'] .
+                '/autoload.php'
+            )
+        )
+    ) {
+        require_once __DIR__ . '/../vendor/autoload.php';
+    }
+})();
 
 use Bamarni\Symfony\Console\Autocomplete\Application;
 

tests/fixtures/acme

@@ -1,7 +1,7 @@
 #!/usr/bin/env php
 <?php
 
-require __DIR__.'/../../vendor/autoload.php';
+require __DIR__.'/../../' . ($_SERVER['COMPOSER_VENDOR_DIR'] ?? 'vendor') . '/autoload.php';
 
 use Symfony\Component\Console\Application;
 use Symfony\Component\Console\Command\Command;