diff --git a/Command/CompleteCommand.php b/Command/CompleteCommand.php
index 11ada4e44..0e35143c3 100644
--- a/Command/CompleteCommand.php
+++ b/Command/CompleteCommand.php
@@ -155,10 +155,10 @@ protected function execute(InputInterface $input, OutputInterface $output): int
                 throw $e;
             }
 
-            return self::FAILURE;
+            return 2;
         }
 
-        return self::SUCCESS;
+        return 0;
     }
 
     private function createCompletionInput(InputInterface $input): CompletionInput
diff --git a/Command/DumpCompletionCommand.php b/Command/DumpCompletionCommand.php
index 6f809e2f1..eaf22be1a 100644
--- a/Command/DumpCompletionCommand.php
+++ b/Command/DumpCompletionCommand.php
@@ -85,7 +85,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         if ($input->getOption('debug')) {
             $this->tailDebugLog($commandName, $output);
 
-            return self::SUCCESS;
+            return 0;
         }
 
         $shell = $input->getArgument('shell') ?? self::guessShell();
@@ -102,12 +102,12 @@ protected function execute(InputInterface $input, OutputInterface $output): int
                 $output->writeln(sprintf('<error>Shell not detected, Symfony shell completion only supports "%s").</>', implode('", "', $supportedShells)));
             }
 
-            return self::INVALID;
+            return 2;
         }
 
         $output->write(str_replace(['{{ COMMAND_NAME }}', '{{ VERSION }}'], [$commandName, $this->getApplication()->getVersion()], file_get_contents($completionFile)));
 
-        return self::SUCCESS;
+        return 0;
     }
 
     private static function guessShell(): string
diff --git a/Helper/QuestionHelper.php b/Helper/QuestionHelper.php
index 10602038c..e236be92a 100644
--- a/Helper/QuestionHelper.php
+++ b/Helper/QuestionHelper.php
@@ -128,7 +128,18 @@ private function doAsk(OutputInterface $output, Question $question)
             }
 
             if (false === $ret) {
+                $isBlocked = stream_get_meta_data($inputStream)['blocked'] ?? true;
+
+                if (!$isBlocked) {
+                    stream_set_blocking($inputStream, true);
+                }
+
                 $ret = $this->readInput($inputStream, $question);
+
+                if (!$isBlocked) {
+                    stream_set_blocking($inputStream, false);
+                }
+
                 if (false === $ret) {
                     throw new MissingInputException('Aborted.');
                 }
@@ -500,13 +511,11 @@ private function isInteractiveInput($inputStream): bool
             return self::$stdinIsInteractive = @posix_isatty(fopen('php://stdin', 'r'));
         }
 
-        if (!\function_exists('exec')) {
+        if (!\function_exists('shell_exec')) {
             return self::$stdinIsInteractive = true;
         }
 
-        exec('stty 2> /dev/null', $output, $status);
-
-        return self::$stdinIsInteractive = 1 !== $status;
+        return self::$stdinIsInteractive = (bool) shell_exec('stty 2> '.('\\' === \DIRECTORY_SEPARATOR ? 'NUL' : '/dev/null'));
     }
 
     /**
diff --git a/Input/InputArgument.php b/Input/InputArgument.php
index ecfcdad58..8a64f7ac8 100644
--- a/Input/InputArgument.php
+++ b/Input/InputArgument.php
@@ -32,7 +32,7 @@ class InputArgument
 
     /**
      * @param string                           $name        The argument name
-     * @param int|null                         $mode        The argument mode: self::REQUIRED or self::OPTIONAL
+     * @param int|null                         $mode        The argument mode: a bit mask of self::REQUIRED, self::OPTIONAL and self::IS_ARRAY
      * @param string                           $description A description text
      * @param string|bool|int|float|array|null $default     The default value (for self::OPTIONAL mode only)
      *
diff --git a/Terminal.php b/Terminal.php
index 04653d3bd..b91e8afc5 100644
--- a/Terminal.php
+++ b/Terminal.php
@@ -64,14 +64,12 @@ public static function hasSttyAvailable(): bool
             return self::$stty;
         }
 
-        // skip check if exec function is disabled
-        if (!\function_exists('exec')) {
+        // skip check if shell_exec function is disabled
+        if (!\function_exists('shell_exec')) {
             return false;
         }
 
-        exec('stty 2>&1', $output, $exitcode);
-
-        return self::$stty = 0 === $exitcode;
+        return self::$stty = (bool) shell_exec('stty 2> '.('\\' === \DIRECTORY_SEPARATOR ? 'NUL' : '/dev/null'));
     }
 
     private static function initDimensions()
diff --git a/Tests/Helper/QuestionHelperTest.php b/Tests/Helper/QuestionHelperTest.php
index 9761e8f97..74315d898 100644
--- a/Tests/Helper/QuestionHelperTest.php
+++ b/Tests/Helper/QuestionHelperTest.php
@@ -430,7 +430,7 @@ public function testAskHiddenResponse()
         $this->assertEquals('8AM', $dialog->ask($this->createStreamableInputInterfaceMock($this->getInputStream("8AM\n")), $this->createOutputInterface(), $question));
     }
 
-    public function testAskHiddenResponseTrimmed()
+    public function testAskHiddenResponseNotTrimmed()
     {
         if ('\\' === \DIRECTORY_SEPARATOR) {
             $this->markTestSkipped('This test is not supported on Windows');
@@ -442,7 +442,7 @@ public function testAskHiddenResponseTrimmed()
         $question->setHidden(true);
         $question->setTrimmable(false);
 
-        $this->assertEquals(' 8AM', $dialog->ask($this->createStreamableInputInterfaceMock($this->getInputStream(' 8AM')), $this->createOutputInterface(), $question));
+        $this->assertEquals(' 8AM'.\PHP_EOL, $dialog->ask($this->createStreamableInputInterfaceMock($this->getInputStream(' 8AM'.\PHP_EOL)), $this->createOutputInterface(), $question));
     }
 
     public function testAskMultilineResponseWithEOF()
diff --git a/Tests/TerminalTest.php b/Tests/TerminalTest.php
index c2d36fe0a..34d32b08e 100644
--- a/Tests/TerminalTest.php
+++ b/Tests/TerminalTest.php
@@ -77,8 +77,8 @@ public function testSttyOnWindows()
             $this->markTestSkipped('Must be on windows');
         }
 
-        $sttyString = exec('(stty -a | grep columns) 2>&1', $output, $exitcode);
-        if (0 !== $exitcode) {
+        $sttyString = shell_exec('(stty -a | grep columns) 2> NUL');
+        if (!$sttyString) {
             $this->markTestSkipped('Must have stty support');
         }