Repository: symfony/symfony
File: src/Symfony/Component/Console/Style/SymfonyStyle.php (PHP)

Code before:
    }

    public function confirm(string $question, bool $default = true): bool
    {
        return $this->askQuestion(new ConfirmationQuestion($question, $default));
    }

    public function choice(string $question, array $choices, mixed $default = null, bool $multiSelect = false): mixed
    {
        if (null !== $default) {
            $values = array_flip($choices);
            $default = $values[$default] ?? $default;
        }

        $questionChoice = new ChoiceQuestion($question, $choices, $default);
        $questionChoice->setMultiselect($multiSelect);

        return $this->askQuestion($questionChoice);
    }

    public function askFile(string $question): ?InputFile
    {
        return $this->askQuestion(new FileQuestion($question));
    }

    public function progressStart(int $max = 0, ?string $format = null): void
    {
        $this->progressBar = $this->createProgressBar($max, $format);
        $this->progressBar->start();
    }

    public function progressAdvance(int $step = 1): void
    {
        $this->getProgressBar()->advance($step);
    }

    public function progressFinish(): void
    {
        $this->getProgressBar()->finish();
        $this->newLine(2);
        unset($this->progressBar);
    }

    public function createProgressBar(int $max = 0, ?string $format = null): ProgressBar
    {
        $progressBar = parent::createProgressBar($max);

        if ('\\' !== \DIRECTORY_SEPARATOR || 'Hyper' === getenv('TERM_PROGRAM')) {
            $progressBar->setEmptyBarCharacter('░'); // light shade character \u2591
            $progressBar->setProgressCharacter('');
            $progressBar->setBarCharacter('▓'); // dark shade character \u2593

Review comment (suggestion):
because the class is not final, adding an argument is a BC break
the way to solve this is to use func_num_args and an `@param`
please have a look at existing similar deprecation, I think there are a few already in branch 8.1, and many in branch 7.4
don't forget to also update the UPGRADE-8.1.md file

Code after:
    }

    public function confirm(string $question, bool $default = true): bool
    {
        return $this->askQuestion(new ConfirmationQuestion($question, $default));
    }

    public function choice(string $question, array $choices, mixed $default = null, bool $multiSelect = false): mixed
    {
        if (null !== $default) {
            $values = array_flip($choices);
            $default = $values[$default] ?? $default;
        }

        $questionChoice = new ChoiceQuestion($question, $choices, $default);
        $questionChoice->setMultiselect($multiSelect);

        return $this->askQuestion($questionChoice);
    }

    public function askFile(string $question): ?InputFile
    {
        return $this->askQuestion(new FileQuestion($question));
    }

    /**
     * @param string|null $format
     */
    public function progressStart(int $max = 0 /* , ?string $format = null */): void
    {
        $format = 2 <= \func_num_args() ? func_get_arg(1) : null;
        $this->progressBar = $this->createProgressBar($max, $format);
        $this->progressBar->start();
    }

    public function progressAdvance(int $step = 1): void
    {
        $this->getProgressBar()->advance($step);
    }

    public function progressFinish(): void
    {
        $this->getProgressBar()->finish();
        $this->newLine(2);
        unset($this->progressBar);
    }

    /**
     * @param string|null $format
     */
    public function createProgressBar(int $max = 0 /* , ?string $format = null */): ProgressBar