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AydinHassanAydinHassan
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Initial safe space for nulls exercise
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6 files changed

+268
-1
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6 files changed

+268
-1
lines changed

‎app/bootstrap.php

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}
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use PhpSchool\PHP8Appreciate\Exercise\AMatchMadeInHeaven;
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use PhpSchool\PHP8Appreciate\Exercise\ASafeSpaceForNulls;
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use PhpSchool\PHP8Appreciate\Exercise\CautionWithCatches;
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use PhpSchool\PHP8Appreciate\Exercise\HaveTheLastSay;
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use PhpSchool\PHP8Appreciate\Exercise\InfiniteDivisions;
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$app->addExercise(LordOfTheStrings::class);
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$app->addExercise(UniteTheTypes::class);
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$app->addExercise(InfiniteDivisions::class);
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$app->addExercise(ASafeSpaceForNulls::class);
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$art = <<<ART
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_ __ _

‎app/config.php

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<?php
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use PhpSchool\PHP8Appreciate\Exercise\AMatchMadeInHeaven;
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use PhpSchool\PHP8Appreciate\Exercise\ASafeSpaceForNulls;
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use PhpSchool\PHP8Appreciate\Exercise\CautionWithCatches;
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use PhpSchool\PHP8Appreciate\Exercise\HaveTheLastSay;
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use PhpSchool\PHP8Appreciate\Exercise\InfiniteDivisions;
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InfiniteDivisions::class => function (ContainerInterface $c) {
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return new InfiniteDivisions($c->get(PhpParser\Parser::class), $c->get(\Faker\Generator::class));
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},
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ASafeSpaceForNulls::class => function (ContainerInterface $c) {
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return new ASafeSpaceForNulls($c->get(PhpParser\Parser::class), $c->get(\Faker\Generator::class));
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},
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];

‎composer.json

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],
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"require": {
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"php": "^8.0",
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"php-school/php-workshop": "dev-master"
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"php-school/php-workshop": "dev-file-comparison-check"
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},
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"require-dev": {
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"phpunit/phpunit": "^9",

‎exercises/a-safe-space-for-nulls/problem/problem.md

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‎exercises/a-safe-space-for-nulls/solution/solution.php

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<?php
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$fp = fopen('users.csv', 'w+');
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fputcsv($fp, ['First Name', 'Last Name', 'Age', 'House num', 'Addr 1', 'Addr 2']);
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fputcsv(
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$fp,
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[
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$user->firstName,
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$user->lastName,
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$user?->age,
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$user?->address?->number,
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$user?->address?->addressLine1,
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$user?->address?->addressLine2
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]
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);
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fclose($fp);

‎src/Exercise/ASafeSpaceForNulls.php

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<?php
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namespace PhpSchool\PHP8Appreciate\Exercise;
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use Faker\Generator as FakerGenerator;
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use Faker\Provider\en_US\Address;
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use Faker\Provider\en_US\Person;
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use PhpParser\BuilderFactory;
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use PhpParser\Node;
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use PhpParser\Node\Expr\Assign;
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use PhpParser\Node\Expr\NullsafePropertyFetch;
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use PhpParser\Node\Expr\Variable;
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use PhpParser\Node\Identifier;
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use PhpParser\Node\NullableType;
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use PhpParser\Node\Stmt;
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use PhpParser\Node\Stmt\Expression;
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use PhpParser\NodeFinder;
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use PhpParser\Parser;
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use PhpSchool\PhpWorkshop\Exercise\AbstractExercise;
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use PhpSchool\PhpWorkshop\Exercise\CliExercise;
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use PhpSchool\PhpWorkshop\Exercise\ExerciseInterface;
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use PhpSchool\PhpWorkshop\Exercise\ExerciseType;
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use PhpSchool\PhpWorkshop\Exercise\SubmissionPatchable;
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use PhpSchool\PhpWorkshop\ExerciseCheck\FileComparisonExerciseCheck;
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use PhpSchool\PhpWorkshop\ExerciseCheck\SelfCheck;
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use PhpSchool\PhpWorkshop\Input\Input;
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use PhpSchool\PhpWorkshop\Patch;
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use PhpSchool\PhpWorkshop\Result\Failure;
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use PhpSchool\PhpWorkshop\Result\ResultInterface;
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use PhpSchool\PhpWorkshop\Result\Success;
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class ASafeSpaceForNulls extends AbstractExercise implements
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ExerciseInterface,
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CliExercise,
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SubmissionPatchable,
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FileComparisonExerciseCheck,
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SelfCheck
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{
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public function __construct(private Parser $parser, private FakerGenerator $faker)
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{
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}
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public function getName(): string
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{
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return 'A Safe Space For Nulls';
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}
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public function getDescription(): string
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{
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return 'PHP 8\'s Null Safe Operator';
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}
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public function getType(): ExerciseType
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{
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return new ExerciseType(ExerciseType::CLI);
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}
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public function getArgs(): array
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{
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return [];
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}
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public function getPatch(): Patch
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{
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$factory = new BuilderFactory();
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$statements = [];
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$statements[] = $factory->class('User')
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->addStmt($factory->property('firstName')->setType('string')->makePublic())
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->addStmt($factory->property('lastName')->setType('string')->makePublic())
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->addStmt($factory->property('age')->setType(new NullableType('int'))->makePublic()->setDefault(null))
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->addStmt($factory->property('address')
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->setType(new NullableType('Address'))
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->makePublic()
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->setDefault(null))
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->getNode();
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$statements[] = $factory->class('Address')
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->addStmt($factory->property('number')->setType('int')->makePublic())
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->addStmt($factory->property('addressLine1')->setType('string')->makePublic())
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->addStmt($factory->property('addressLine2')
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->setType(new NullableType('string'))
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->makePublic()
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->setDefault(null))
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->getNode();
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$addressFaker = new Address($this->faker);
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$personFaker = new Person($this->faker);
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$statements[] = new Expression(
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new Assign($factory->var('user'), $factory->new('User'))
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);
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch($factory->var('user'), 'firstName'),
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$factory->val($personFaker->firstName())
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)
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);
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch($factory->var('user'), 'lastName'),
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$factory->val($personFaker->lastName())
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)
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);
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if ($this->faker->boolean()) {
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch($factory->var('user'), 'age'),
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$factory->val($this->faker->numberBetween(18, 100))
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)
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);
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}
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if ($this->faker->boolean()) {
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch($factory->var('user'), 'address'),
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$factory->new('Address')
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)
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);
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch(
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$factory->propertyFetch($factory->var('user'), 'address'),
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'number'
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),
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$factory->val($addressFaker->buildingNumber())
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)
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);
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch(
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$factory->propertyFetch($factory->var('user'), 'address'),
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'addressLine1'
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),
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$factory->val($addressFaker->streetName())
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)
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);
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if ($this->faker->boolean()) {
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$statements[] = new Expression(
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new Assign(
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$factory->propertyFetch(
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$factory->propertyFetch($factory->var('user'), 'address'),
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'addressLine2'
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),
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$factory->val($addressFaker->secondaryAddress())
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)
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);
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}
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}
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return (new Patch())
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->withTransformer(function (array $originalStatements) use ($statements) {
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return array_merge($statements, $originalStatements);
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});
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}
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public function check(Input $input): ResultInterface
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{
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/** @var array<Stmt> $statements */
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$statements = $this->parser->parse((string) file_get_contents($input->getRequiredArgument('program')));
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$ageFetch = $this->findNullSafePropFetch($statements, 'user', 'age');
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$addressFetch = $this->findAllNullSafePropertyFetch($statements, 'user', 'address');
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if ($ageFetch === null) {
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return new Failure(
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$this->getName(),
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'The $user->age property should be accessed with the null safe operator'
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);
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}
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if (count($addressFetch) !== 3) {
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return new Failure(
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$this->getName(),
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'The $user->address property should always be accessed with the null safe operator'
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);
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}
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$props = [
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'$user->address->number' => $this->findNestedNullSafePropFetch($statements, 'user', 'number'),
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'$user->address->addressLine1' => $this->findNestedNullSafePropFetch($statements, 'user', 'addressLine1'),
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'$user->address->addressLine2' => $this->findNestedNullSafePropFetch($statements, 'user', 'addressLine2'),
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];
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foreach ($props as $prop => $node) {
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if ($node === null) {
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return new Failure(
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$this->getName(),
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"The $prop property should be accessed with the null safe operator"
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);
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}
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}
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return new Success($this->getName());
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}
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/**
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* @param array<Node> $statements
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*/
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private function findNullSafePropFetch(array $statements, string $variableName, string $propName): ?Node
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{
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$nodes = $this->findAllNullSafePropertyFetch($statements, $variableName, $propName);
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return count($nodes) > 0 ? $nodes[0] : null;
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}
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/**
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* @param array<Node> $statements
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* @return array<Node>
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*/
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private function findAllNullSafePropertyFetch(array $statements, string $variableName, string $propName): array
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{
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return (new NodeFinder())->find($statements, function (Node $node) use ($variableName, $propName) {
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return $node instanceof NullsafePropertyFetch
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&& $node->var instanceof Variable
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&& $node->var->name === $variableName
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&& $node->name instanceof Identifier
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&& $node->name->name === $propName;
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});
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}
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/**
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* @param array<Node> $statements
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*/
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private function findNestedNullSafePropFetch(array $statements, string $variableName, string $propName): ?Node
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{
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return (new NodeFinder())->findFirst($statements, function (Node $node) use ($variableName, $propName) {
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return $node instanceof NullsafePropertyFetch
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&& $node->var instanceof NullsafePropertyFetch
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&& $node->var->var instanceof Variable
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&& $node->var->var->name === $variableName
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&& $node->name instanceof Identifier
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&& $node->name->name === $propName;
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});
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}
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public function getFilesToCompare(): array
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{
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return [
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'users.csv'
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];
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}
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}

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