[Console] invalid default returned from ChoiceQuestion on non interactive mode

[ThHareau]

Symfony version(s) affected: symfony/console v4.2.3

Description

ChoiceQuestion returns the index in interactive mode but the value in non interactive mode

How to reproduce
Using this command:

class TestCommand extends Command
{
    protected function configure()
    {
        $this->setName('test');
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $choices = [
            'a' => 'aaaa',
            'b' => 'bbbb',
        ];

        $questionHelper = new SymfonyQuestionHelper();
        $choice = $questionHelper->ask(
            $input,
            $output,
            new ChoiceQuestion('Does it work?', $choices, 'a')
        );

        $output->writeln("Choice: $choice");
    }
}

Then php bin/console test or php bin/console -n will not display the same value.

Possible Solution

https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Console/Helper/QuestionHelper.php#L56 should probably return default, and not the value.

Additional context
The opposite bug with reported in #25470 , the non-interactive mode was returning the index instead of the value. I suppose the return value was changed from value to index meanwhile?

[jschaedl]

When you follow the symfony docs to create a ChoiceQuestion:

$question = new ChoiceQuestion(
        'Please select your favorite color (defaults to red)',
        ['red', 'blue', 'yellow'],
        0
    );

it will display the same output for bin/console test or bin/console test -n

See https://symfony.com/doc/current/components/console/helpers/questionhelper.html#let-the-user-choose-from-a-list-of-answers for more information and try to update your code to:

class TestCommand extends Command
{
    ...

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $choices = ['yes', 'no'];

        $question = new ChoiceQuestion('Does it work?', $choices, 0);

        $questionHelper = new SymfonyQuestionHelper();
        $choice = $questionHelper->ask($input, $output, $question);

        $output->writeln("Choice: " . $choice);
    }
}

[chalasr]

The inconsistent result happens when using string keys for choices, the ChoiceQuestion default validator returns the key if it’s a string: https://github.com/symfony/console/blob/f6f44ce1c9513a37b8826ce7f3edd26d6ab7bf09/Question/ChoiceQuestion.php#L160
The difference is that the validator is not called in non-interactive mode, which is inconsistent.
I will submit a patch.

[ThHareau]

Thanks 👍