infection / infection

src/Command/BaseCommand.php

<?php
/**
 * This code is licensed under the BSD 3-Clause License.
 *
 * Copyright (c) 2017, Maks Rafalko
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * * Neither the name of the copyright holder nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

declare(strict_types=1);

namespace Infection\Command;

use Infection\Console\Application;

The type Infection\Console\Application was not found. Maybe you did not declare it correctly or list all dependencies?

use Infection\Console\IO;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Webmozart\Assert\Assert;

/**
 * @internal
 */
abstract class BaseCommand extends Command
{
    /**
     * @var IO|null
     */
    private $io;

    final public function getApplication(): Application
    {
        $application = parent::getApplication();

        Assert::isInstanceOf(
            $application,
            Application::class,
            'Cannot access to the command application if the command has not been '
            . 'registered to the application yet'
        );

        return $application;

The expression return $application returns the type Symfony\Component\Console\Application|null which is incompatible with the type-hinted return Infection\Console\Application.

    }

    protected function initialize(InputInterface $input, OutputInterface $output): void
    {
        parent::initialize($input, $output);

        $this->io = new IO($input, $output);
    }

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        $this->executeCommand($this->getIO());

        return 0;
    }

    abstract protected function executeCommand(IO $io): void;

    final protected function getIO(): IO
    {
        Assert::notNull(
            $this->io,
            'Cannot retrieve the IO object before the command was initialized'
        );

        return $this->io;

The expression return $this->io could return the type null which is incompatible with the type-hinted return Infection\Console\IO. Consider adding an additional type-check to rule them out.

    }
}