diff --git a/Application.php b/Application.php
index 410900cc2..acd326878 100644
--- a/Application.php
+++ b/Application.php
@@ -36,7 +36,6 @@
 use Symfony\Component\Console\Input\InputDefinition;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
-use Symfony\Component\Console\Input\StreamableInputInterface;
 use Symfony\Component\Console\Output\ConsoleOutput;
 use Symfony\Component\Console\Output\ConsoleOutputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
@@ -947,16 +946,6 @@ protected function configureIO(InputInterface $input, OutputInterface $output)
 
         if (true === $input->hasParameterOption(['--no-interaction', '-n'], true)) {
             $input->setInteractive(false);
-        } elseif (\function_exists('posix_isatty')) {
-            $inputStream = null;
-
-            if ($input instanceof StreamableInputInterface) {
-                $inputStream = $input->getStream();
-            }
-
-            if (!@posix_isatty($inputStream) && false === getenv('SHELL_INTERACTIVE')) {
-                $input->setInteractive(false);
-            }
         }
 
         switch ($shellVerbosity = (int) getenv('SHELL_VERBOSITY')) {
diff --git a/Tester/ApplicationTester.php b/Tester/ApplicationTester.php
index ced56cff2..4f99da18d 100644
--- a/Tester/ApplicationTester.php
+++ b/Tester/ApplicationTester.php
@@ -59,19 +59,12 @@ public function run(array $input, $options = [])
             $this->input->setInteractive($options['interactive']);
         }
 
-        $shellInteractive = getenv('SHELL_INTERACTIVE');
-
         if ($this->inputs) {
             $this->input->setStream(self::createStream($this->inputs));
-            putenv('SHELL_INTERACTIVE=1');
         }
 
         $this->initOutput($options);
 
-        $this->statusCode = $this->application->run($this->input, $this->output);
-
-        putenv($shellInteractive ? "SHELL_INTERACTIVE=$shellInteractive" : 'SHELL_INTERACTIVE');
-
-        return $this->statusCode;
+        return $this->statusCode = $this->application->run($this->input, $this->output);
     }
 }
diff --git a/Tests/phpt/uses_stdin_as_interactive_input.phpt b/Tests/phpt/uses_stdin_as_interactive_input.phpt
new file mode 100644
index 000000000..db1bb4ce4
--- /dev/null
+++ b/Tests/phpt/uses_stdin_as_interactive_input.phpt
@@ -0,0 +1,28 @@
+--STDIN--
+Hello World
+--FILE--
+<?php
+
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Helper\QuestionHelper;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Question\Question;
+
+$vendor = __DIR__;
+while (!file_exists($vendor.'/vendor')) {
+    $vendor = \dirname($vendor);
+}
+require $vendor.'/vendor/autoload.php';
+
+(new Application())
+    ->register('app')
+    ->setCode(function(InputInterface $input, OutputInterface $output) {
+        $output->writeln((new QuestionHelper())->ask($input, $output, new Question('Foo?')));
+    })
+    ->getApplication()
+    ->setDefaultCommand('app', true)
+    ->run()
+;
+--EXPECT--
+Foo?Hello World