Refactoring legacy PHP app

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Refactoring legacy PHP app Nemanja Marić maki10

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About me ● PHP Developer at Orange Hill Development ● Member of PHP Serbia Community ● Co-organizer Laravel Serbia Meetup’s and PHP Serbia Meetup’s ● Working with PHP since 2014 ● In Laravel world from 2016 ● Open source contributor ● Contributing to the Laravel Framework ● And most !important: Husband and father of two little angels

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Interesting part Share your knowledge with others to get some knowledge.

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Over the years

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Covid years

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What will be refactored?

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It’s an old Laravel project started on Laravel 5.4 and PHP 5.6, upgraded to Laravel 6 (migrated 3 times) and PHP 7.3 Our goal is to run it on Laravel 9 (Up 3 major version) and PHP 8.1

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Which tools we will use?

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Rector 1. Instant Upgrades Rector now supports upgrades from PHP 5.3 to 8.0 and major open-source projects like Symfony, PHPUnit, Nette, Laravel, CakePHP, Doctrine, PHPOffice and TYPO3 out of the box. Do you want to be constantly on the latest PHP/framework version without effort? Use Rector to handle instant upgrades for you. 2. Automated Refactoring Do you have code quality you need, but struggle to keep it with new developers in your team? Do you want to see smart code-reviews even when every senior developers sleeps? Add Rector to your CI and let it continuously refactor your code and keep the code quality high.

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Simple rule

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Ok, stop.. Do you trust automated tools to change your code?

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Ok, but what about a big ball of mud?

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We don’t have time to refactor whole application, so let’s start one by one

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Big complexity Poorly designed code is often complex and architecturally all off. Like it or not, that is only and only our mistake as developers. This is something that no tool can help you with, so let's dig in.

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With the power of a “phpinsights” we can spot issues, let’s warm up

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[Code] Useless parentheses: Line:149

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[Code] Nullable type for null default value: Line:82

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Cyclomatic Complexity

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Complexity is determined by the number of decision points in a method plus one for the method entry. The decision points are 'if', 'while', 'for', and 'case labels'. Generally, 1-4 is low complexity, 5-7 indicates moderate complexity, 8-10 is high complexity, and 11+ is very high complexity.

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Lower complexity = less issues [Complexity] Having `classes` with more than 5 cyclomatic complexity is prohibited - Consider refactoring: TransformationController.php: 17 cyclomatic complexity

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Strategy pattern

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Rector rule [email protected] | Strategy pattern

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Model Transformer

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Model Transformer | Can be better?

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Yes of course | Can be better?

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How about to concat arrays and search both params to see if exist and to get the first one?!?

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Let’s see whole refactor score

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[COMPLEXITY] 60.6 pts with average of 1.82 from 17 cyclomatic complexity

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What is left to do with this?

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The new colleague will easily join when refactor is good

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Change from instanceof to class_implements

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[COMPLEXITY] 60.6 pts with average of 1.45 from 17 cyclomatic complexity

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Ok, and last, how to stop new shitty code, and set some rules for it?

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Questions? Slides: https://speakerdeck.com/maki10 Twitter: https://twitter.com/NemanjaMaki10 https://github.com/rectorphp/rector https://github.com/phpstan/phpstan https://github.com/nunomaduro/phpinsights