Fix/normalize tty handling

src/Composer/Console/Application.php

@@ -129,12 +129,7 @@ class Application extends BaseApplication
     {
         $this->disablePluginsByDefault = $input->hasParameterOption('--no-plugins');
 
-        if (
+        if (getenv('COMPOSER_NO_INTERACTION') || !Platform::isTty(STDIN)) {
-            getenv('COMPOSER_NO_INTERACTION')
-            /* @see \Composer\Util\ProcessExecutor::executeTty - tty test */
-            || (function_exists('stream_isatty') && !stream_isatty(STDOUT))
-            || (function_exists('posix_isatty') && !posix_isatty(STDOUT))
-        ) {
             $input->setInteractive(false);
         }
 

src/Composer/Util/Platform.php

@@ -89,4 +89,26 @@ class Platform
 
         return \strlen($str);
     }
+
+    public static function isTty($fd = null)
+    {
+        if ($fd === null) {
+            $fd = STDOUT;
+        }
+
+        // modern cross-platform function, includes the fstat
+        // fallback so if it is present we trust it
+        if (function_exists('stream_isatty')) {
+            return stream_isatty($fd);
+        }
+
+        // only trusting this if it is positive, otherwise prefer fstat fallback
+        if (function_exists('posix_isatty') && posix_isatty($fd)) {
+            return true;
+        }
+
+        $stat = @fstat($fd);
+        // Check if formatted mode is S_IFCHR
+        return $stat ? 0020000 === ($stat['mode'] & 0170000) : false;
+    }
 }

src/Composer/Util/ProcessExecutor.php

@@ -77,15 +77,11 @@ class ProcessExecutor
      */
     public function executeTty($command, $cwd = null)
     {
-        if (
+        if (Platform::isTty()) {
-            /* @see \Composer\Console\Application::doRun - tty test */
+            return $this->doExecute($command, $cwd, true);
-            (function_exists('stream_isatty') && !stream_isatty(STDOUT))
-            || (function_exists('posix_isatty') && !posix_isatty(STDOUT))
-        ) {
-            return $this->doExecute($command, $cwd, false);
         }
 
-        return $this->doExecute($command, $cwd, true);
+        return $this->doExecute($command, $cwd, false);
     }
 
     private function doExecute($command, $cwd, $tty, &$output = null)