[Forwardport] Fix possible undefined index when caching config data

[mage2pratik]

Original Pull Request

#13649

Description

Fix possible undefined index when caching config data.

This replicates as per below steps to replicate.

Manual testing scenarios

1. Install clean Magento 2.2 with the following commands:

cd /var/www/temp
git clone git@github.com:magento/magento2.git --branch 2.2-develop
cd magento2
composer --no-ansi --no-interaction install --no-progress --prefer-dist --optimize-autoloader --no-dev

2. In order to replicate the issue, we will need to add some action which connects to config data during build command. We will add a logger processor which does add request_uri value for every log message, if the configuration flag dev/log/request_uri is enabled. The following sub-steps add a new logger processor in Magento_Developer module:

• Add in file /var/www/temp/magento2/app/code/Magento/Developer/etc/di.xml the following content under <config> tag:

    <type name="\Magento\Framework\Logger\Monolog">
        <arguments>
            <argument name="processors" xsi:type="array">
                <item name="Magento_Developer" xsi:type="object">\Magento\Developer\Logger\Processor</item>
            </argument>
        </arguments>
    </type>

• Add new file in
  /var/www/temp/magento2/app/code/Magento/Developer/Logger/Processor.php with the following content:

<?php
namespace Magento\Developer\Logger;

class Processor
{
    /** @var \Magento\Framework\App\Config\ScopeConfigInterface */
    private $scopeConfig;

    public function __construct(
        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
    ) {
        $this->scopeConfig = $scopeConfig;
    }

    public function __invoke($record)
    {
        if ($this->scopeConfig->isSetFlag('dev/log/request_uri') && is_array($record)) {
            if (!isset($record['extra'])) {
                $record['extra'] = [];
            }
            $record['extra']['request_uri'] = $_SERVER['REQUEST_URI'] ?? null;
        }

        return $record;
    }
}

3. Run the following two commands which are part of usual build procedure:

php bin/magento module:enable --all
php bin/magento setup:di:compile -v

Expected
Command setup:di:compile is successful.

Actual
Command setup:di:compile is not successful.
The following error occurs:

  [Exception]
  Notice: Undefined index: websites in /private/var/www/temp/magento2/app/code/Magento/Config/App/Config/Type/System.php on line 248


Exception trace:
 () at /private/var/www/temp/magento2/lib/internal/Magento/Framework/App/ErrorHandler.php:61
 Magento\Framework\App\ErrorHandler->handler() at /private/var/www/temp/magento2/app/code/Magento/Config/App/Config/Type/System.php:248
 Magento\Config\App\Config\Type\System->cacheData() at /private/var/www/temp/magento2/app/code/Magento/Config/App/Config/Type/System.php:192
 Magento\Config\App\Config\Type\System->loadDefaultScopeData() at /private/var/www/temp/magento2/app/code/Magento/Config/App/Config/Type/System.php:152
 Magento\Config\App\Config\Type\System->get() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/App/Config.php:131
 Magento\Framework\App\Config->get() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/App/Config.php:80
 Magento\Framework\App\Config->getValue() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/App/Config.php:93
 Magento\Framework\App\Config->isSetFlag() at /private/var/www/temp/magento2/app/code/Magento/Developer/Logger/Processor.php:23
 Magento\Developer\Logger\Processor->__invoke() at n/a:n/a
 call_user_func() at /private/var/www/temp/magento2/vendor/monolog/monolog/src/Monolog/Logger.php:333
 Monolog\Logger->addRecord() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/Logger/Monolog.php:48
 Magento\Framework\Logger\Monolog->addRecord() at /private/var/www/temp/magento2/vendor/monolog/monolog/src/Monolog/Logger.php:532
 Monolog\Logger->debug() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/Cache/InvalidateLogger.php:42
 Magento\Framework\Cache\InvalidateLogger->execute() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/Cache/Frontend/Decorator/Logger.php:58
 Magento\Framework\Cache\Frontend\Decorator\Logger->log() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/Cache/Frontend/Decorator/Logger.php:48
 Magento\Framework\Cache\Frontend\Decorator\Logger->clean() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/App/Cache.php:102
 Magento\Framework\App\Cache->clean() at /private/var/www/temp/magento2/setup/src/Magento/Setup/Console/Command/DiCompileCommand.php:152
 Magento\Setup\Console\Command\DiCompileCommand->execute() at /private/var/www/temp/magento2/vendor/symfony/console/Command/Command.php:242
 Symfony\Component\Console\Command\Command->run() at /private/var/www/temp/magento2/vendor/symfony/console/Application.php:842
 Symfony\Component\Console\Application->doRunCommand() at /private/var/www/temp/magento2/vendor/symfony/console/Application.php:193
 Symfony\Component\Console\Application->doRun() at /private/var/www/temp/magento2/lib/internal/Magento/Framework/Console/Cli.php:104
 Magento\Framework\Console\Cli->doRun() at /private/var/www/temp/magento2/vendor/symfony/console/Application.php:117
 Symfony\Component\Console\Application->run() at /private/var/www/temp/magento2/bin/magento:23

setup:di:compile

Note that valid code added in the previous steps does trigger the above error. The exception trace contains line:

/private/var/www/temp/magento2/app/code/Magento/Developer/Logger/Processor.php:23

Explanation
The error occurs because at this step of loading config data, there are no stores and no websites since Magento is not installed. As a consequence, config data does not contain any store-specific or website-specific configurations.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @mage2pratik. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me {$VERSION} instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Assistant documentation

[magento-engcom-team]

Hi @VladimirZaets, thank you for the review.
ENGCOM-2754 has been created to process this Pull Request

[magento-engcom-team]

Hi @mage2pratik. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.