bug #36031 [Console] Fallback to default answers when unable to read input (ostrolucky)

This PR was merged into the 4.4 branch.

Discussion
----------

[Console] Fallback to default answers when unable to read input

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #36027, Fix #35988
| License       | MIT
| Doc PR        |

Alternative to https://github.com/symfony/symfony/pull/36027.

This fixes linked issues without having to revert fix for #30726. Successfully tested with composer script, `docker run` and `docker run -it`.

Commits
-------

8ddaa20b29 [Console] Fallback to default answers when unable to read input

src/Symfony/Component/Console/Exception/MissingInputException.php

@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Console\Exception;
+
+/**
+ * Represents failure to read input from stdin.
+ *
+ * @author Gabriel Ostrolucký <gabriel.ostrolucky@gmail.com>
+ */
+class MissingInputException extends RuntimeException implements ExceptionInterface
+{
+}

src/Symfony/Component/Console/Helper/QuestionHelper.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Console\Helper;
 
+use Symfony\Component\Console\Exception\MissingInputException;
 use Symfony\Component\Console\Exception\RuntimeException;
 use Symfony\Component\Console\Formatter\OutputFormatter;
 use Symfony\Component\Console\Formatter\OutputFormatterStyle;
@@ -48,44 +49,32 @@ class QuestionHelper extends Helper
         }
 
         if (!$input->isInteractive()) {
-            $default = $question->getDefault();
+            return $this->getDefaultAnswer($question);
-
-            if (null === $default) {
-                return $default;
-            }
-
-            if ($validator = $question->getValidator()) {
-                return \call_user_func($question->getValidator(), $default);
-            } elseif ($question instanceof ChoiceQuestion) {
-                $choices = $question->getChoices();
-
-                if (!$question->isMultiselect()) {
-                    return isset($choices[$default]) ? $choices[$default] : $default;
-                }
-
-                $default = explode(',', $default);
-                foreach ($default as $k => $v) {
-                    $v = $question->isTrimmable() ? trim($v) : $v;
-                    $default[$k] = isset($choices[$v]) ? $choices[$v] : $v;
-                }
-            }
-
-            return $default;
         }
 
         if ($input instanceof StreamableInputInterface && $stream = $input->getStream()) {
             $this->inputStream = $stream;
         }
 
-        if (!$question->getValidator()) {
+        try {
-            return $this->doAsk($output, $question);
+            if (!$question->getValidator()) {
+                return $this->doAsk($output, $question);
+            }
+
+            $interviewer = function () use ($output, $question) {
+                return $this->doAsk($output, $question);
+            };
+
+            return $this->validateAttempts($interviewer, $output, $question);
+        } catch (MissingInputException $exception) {
+            $input->setInteractive(false);
+
+            if (null === $fallbackOutput = $this->getDefaultAnswer($question)) {
+                throw $exception;
+            }
+
+            return $fallbackOutput;
         }
-
-        $interviewer = function () use ($output, $question) {
-            return $this->doAsk($output, $question);
-        };
-
-        return $this->validateAttempts($interviewer, $output, $question);
     }
 
     /**
@@ -134,7 +123,7 @@ class QuestionHelper extends Helper
             if (false === $ret) {
                 $ret = fgets($inputStream, 4096);
                 if (false === $ret) {
-                    throw new RuntimeException('Aborted.');
+                    throw new MissingInputException('Aborted.');
                 }
                 if ($question->isTrimmable()) {
                     $ret = trim($ret);
@@ -158,6 +147,36 @@ class QuestionHelper extends Helper
         return $ret;
     }
 
+    /**
+     * @return mixed
+     */
+    private function getDefaultAnswer(Question $question)
+    {
+        $default = $question->getDefault();
+
+        if (null === $default) {
+            return $default;
+        }
+
+        if ($validator = $question->getValidator()) {
+            return \call_user_func($question->getValidator(), $default);
+        } elseif ($question instanceof ChoiceQuestion) {
+            $choices = $question->getChoices();
+
+            if (!$question->isMultiselect()) {
+                return isset($choices[$default]) ? $choices[$default] : $default;
+            }
+
+            $default = explode(',', $default);
+            foreach ($default as $k => $v) {
+                $v = $question->isTrimmable() ? trim($v) : $v;
+                $default[$k] = isset($choices[$v]) ? $choices[$v] : $v;
+            }
+        }
+
+        return $default;
+    }
+
     /**
      * Outputs the question prompt.
      */
@@ -240,7 +259,7 @@ class QuestionHelper extends Helper
             // as opposed to fgets(), fread() returns an empty string when the stream content is empty, not false.
             if (false === $c || ('' === $ret && '' === $c && null === $question->getDefault())) {
                 shell_exec(sprintf('stty %s', $sttyMode));
-                throw new RuntimeException('Aborted.');
+                throw new MissingInputException('Aborted.');
             } elseif ("\177" === $c) { // Backspace Character
                 if (0 === $numMatches && 0 !== $i) {
                     --$i;
@@ -406,7 +425,7 @@ class QuestionHelper extends Helper
             shell_exec(sprintf('stty %s', $sttyMode));
 
             if (false === $value) {
-                throw new RuntimeException('Aborted.');
+                throw new MissingInputException('Aborted.');
             }
             if ($trimmable) {
                 $value = trim($value);

src/Symfony/Component/Console/Tests/Helper/QuestionHelperTest.php

@@ -696,7 +696,7 @@ class QuestionHelperTest extends AbstractQuestionHelperTest
 
     public function testAskThrowsExceptionOnMissingInput()
     {
-        $this->expectException('Symfony\Component\Console\Exception\RuntimeException');
+        $this->expectException('Symfony\Component\Console\Exception\MissingInputException');
         $this->expectExceptionMessage('Aborted.');
         $dialog = new QuestionHelper();
         $dialog->ask($this->createStreamableInputInterfaceMock($this->getInputStream('')), $this->createOutputInterface(), new Question('What\'s your name?'));
@@ -704,7 +704,7 @@ class QuestionHelperTest extends AbstractQuestionHelperTest
 
     public function testAskThrowsExceptionOnMissingInputForChoiceQuestion()
     {
-        $this->expectException('Symfony\Component\Console\Exception\RuntimeException');
+        $this->expectException('Symfony\Component\Console\Exception\MissingInputException');
         $this->expectExceptionMessage('Aborted.');
         $dialog = new QuestionHelper();
         $dialog->ask($this->createStreamableInputInterfaceMock($this->getInputStream('')), $this->createOutputInterface(), new ChoiceQuestion('Choice', ['a', 'b']));
@@ -712,7 +712,7 @@ class QuestionHelperTest extends AbstractQuestionHelperTest
 
     public function testAskThrowsExceptionOnMissingInputWithValidator()
     {
-        $this->expectException('Symfony\Component\Console\Exception\RuntimeException');
+        $this->expectException('Symfony\Component\Console\Exception\MissingInputException');
         $this->expectExceptionMessage('Aborted.');
         $dialog = new QuestionHelper();
 

src/Symfony/Component/Console/Tests/phpt/uses_stdin_as_interactive_input.phpt

@@ -18,7 +18,8 @@ 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?')));
+        $output->writeln((new QuestionHelper())->ask($input, $output, new Question('Foo?', 'foo')));
+        $output->writeln((new QuestionHelper())->ask($input, $output, new Question('Bar?', 'bar')));
     })
     ->getApplication()
     ->setDefaultCommand('app', true)
@@ -26,3 +27,4 @@ require $vendor.'/vendor/autoload.php';
 ;
 --EXPECT--
 Foo?Hello World
+Bar?bar