Tackling Tech Debt with Rector
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The document discusses managing technical debt within Spreaker, a podcast platform that is part of the iHeartMedia family. It introduces Rector, a tool for automated refactoring that helps address technical debt by applying complex code manipulations through defined rules. The document outlines installation, configuration details, and how to create custom rules to enhance code quality and maintainability.
![rector.php
<?php
return static function (RectorConfig $rectorConfig): void {
$rectorConfig->paths([
__DIR__ . '/apps',
__DIR__ . '/lib',
__DIR__ . '/test',
]);
$rectorConfig->rule(AddContainerAwareIfNotPresent::class);
$rectorConfig->rule(MigrateSpUtilStaticCallsRector::class);
};](https://image.slidesharecdn.com/fightingtechnicaldebtwithrector-230308082642-3f6a8649/85/Tackling-Tech-Debt-with-Rector-12-320.jpg)
![rector.php
<?php
return static function (RectorConfig $rectorConfig): void {
$rectorConfig->paths([
__DIR__ . '/apps',
__DIR__ . '/lib',
__DIR__ . '/test',
]);
$rectorConfig->sets([SetList::DEAD_CODE, SetList::PHP_82]);
};](https://image.slidesharecdn.com/fightingtechnicaldebtwithrector-230308082642-3f6a8649/85/Tackling-Tech-Debt-with-Rector-21-320.jpg)
![rector.php
<?php
return static function (RectorConfig $rectorConfig): void {
$rectorConfig->paths([
__DIR__ . '/apps',
__DIR__ . '/lib',
__DIR__ . '/test',
]);
$rectorConfig->sets([LevelSetList::UP_TO_PHP_82]);
};](https://image.slidesharecdn.com/fightingtechnicaldebtwithrector-230308082642-3f6a8649/85/Tackling-Tech-Debt-with-Rector-23-320.jpg)
Tackling Tech Debt with Rector
- 3. ● Spreaker is a podcast platform ● Within Spreaker, podcasts can be hosted, distributed, monetized, discovered, and listened to ● Part of iHeartMedia family since 2020
- 4. 🤓 Expert teams can tame it, choosing willingly to accumulate it → trade off cleaner solution with a good enough one Tech Debt 🐥 Green teams accumulate it unconsciously → let's try this and that Never saw a project without it 🙄
- 5. The mere fact that we are writing code exposes us to tech debt Tech Debt -> Language Evolves -> Libraries evolve -> Frameworks evolve -> Things are (re)discovered
- 6. How can we deal with it? Invest 🕒 and ⚡ to repay the debt 😫 Sometimes it is hard to justify the investment 🤔 Is there a way to get away with it? Tech Debt
- 7. Performs automated refactorings on a codebase It provides a list of predefined rectors, aka rules, refactorings you can choose to apply on your codebase, via a rector.php config file. E.g. - Change a property access with a method call from $obj->property to $obj->method() - Substitute class invocation with another one from Banana::method() to Apple::anotherMethod() Rector
- 8. Provided a ton of rules out of the box - Code style/quality - Manipulate properties/methods - Upgrade language version - Upgrade framework version Rector https://github.com/rectorphp/rector/blob/main/docs/rector_rules_overview.md
- 9. Why do I need it? -> Regexp are not enough? -> Search and replace is not enough? Rectors parses the code, so it can perform complex manipulation. For this reason it is also unaffected by code formatting (spaces, newlines, …) Rector
- 10. Installation/configuration $ composer require rector/rector --dev If you create custom rules, configure composer.json to enable autoload "autoload-dev": { "psr-4": { "UtilsRector": "tools/php/rector/src", "UtilsRectorTests": "tools/php/rector/tests" } }
- 11. Installation/configuration Create an empty rector.php file in the project root directory $ vendor/bin/rector init Change rector.php to specify which directories should be scanned and which rules should be applied
- 12. rector.php <?php return static function (RectorConfig $rectorConfig): void { $rectorConfig->paths([ __DIR__ . '/apps', __DIR__ . '/lib', __DIR__ . '/test', ]); $rectorConfig->rule(AddContainerAwareIfNotPresent::class); $rectorConfig->rule(MigrateSpUtilStaticCallsRector::class); };
- 13. Run In the project root directory run $ vendor/bin/rector process If you want to see a preview of the changes without touching the files $ vendor/bin/rector process --dry-run
- 14. Rules
- 18. Configurable Rules Rule accepting configuration params
- 20. SetLists Define a group of rules to avoid specify them one by one
- 21. rector.php <?php return static function (RectorConfig $rectorConfig): void { $rectorConfig->paths([ __DIR__ . '/apps', __DIR__ . '/lib', __DIR__ . '/test', ]); $rectorConfig->sets([SetList::DEAD_CODE, SetList::PHP_82]); };
- 22. LevelSetLists Applies all the rules up to a certain PHP version
- 23. rector.php <?php return static function (RectorConfig $rectorConfig): void { $rectorConfig->paths([ __DIR__ . '/apps', __DIR__ . '/lib', __DIR__ . '/test', ]); $rectorConfig->sets([LevelSetList::UP_TO_PHP_82]); };
- 24. 1. Loads configuration from rector.php 2. Iterates all files 3. For each file a. Preparation phase: parse file, creates AST (array of nodes), add some metadata b. Rectify Phase i. Traverse AST ii. Check if rectors can be applied to that node iii. If yse, apply c. Save/Diff phase How it works
- 25. A rule is a PHP class that extends AbstractRector Implement 3 method Writing Custom Rules public function getRuleDefinition(): RuleDefinition public function getNodeTypes(): array public function refactor(Node $node): ?Node
- 26. Life of a PHP file 🐘
- 27. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } }
- 28. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 29. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 30. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 31. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 32. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 33. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 34. <?php namespace AppTime; class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 35. <?php namespace AppTime; c class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 36. <?php namespace AppTime; c class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer
- 37. <?php namespace AppTime; c class Clock { public function now() { return date('Y-m-d'); } } T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Tokenizer token_get_all
- 38. T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Parser
- 39. T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Parser
- 40. T_OPEN_TAG ('<?php') T_NAMESPACE ('namespace') T_WHITESPACE (' ') T_STRING ('App') T_NS_SEPARATOR ('') T_STRING ('Time') T_WHITESPACE (' ') T_CLASS ('class') T_WHITESPACE (' ') T_STRING ('Clock') T_WHITESPACE (' ') T_WHITESPACE (' ') T_PUBLIC ('public') T_WHITESPACE (' ') T_FUNCTION ('function') T_WHITESPACE (' ') T_STRING ('now') T_WHITESPACE (' ') T_WHITESPACE ('') T_RETURN ('return') T_WHITESPACE (' ') T_STRING ('date') T_CONSTANT_ENCAPSED_STRING (''Y-m-d'') T_WHITESPACE ('') T_WHITESPACE ('') T_WHITESPACE ('') Parser AST: Abstract Syntax Tree PHP-Parser
- 45. AST - Abstract Syntax Tree Intermediate representation of the source code Machine friendly Tree structure Traversing the AST means traversing the original source code
- 48. A rule is a PHP class that extends AbstractRector Implement 3 method Writing Custom Rules public function getRuleDefinition(): RuleDefinition public function getNodeTypes(): array public function refactor(Node $node): ?Node
- 49. Look for existing rules that perform similar tasks. Use it as a starting point. Look for helper classes: classes that perform some heavy lifting for you. E.g pull up a property There are plenty: - ClassDependencyManipulator - ClassInsertManipulator - NodeFactory - ParamAnalyzer Create a small snippet of code to test it with --dry-run Start with an existing rule
- 50. Let's 👀 at the code…
- 51. Look for a rule that does something similar to what you need and use it as a starting point This part is a bit time consuming, there are multiple ways to achieve the same result Don't try to do too much in a single rule, combine multiple rules Writing Custom Rules: lesson learned
- 52. Get all the corner cases is hard, Pareto rulez! NodeDumper is your friend Create a Dummy snippet for quick testing Writing Custom Rules: lesson learned
- 53. Extensions: composer installable set of rules for specific framework/libraries These are provided out of the box https://github.com/rectorphp/rector-symfony https://github.com/rectorphp/rector-doctrine https://github.com/rectorphp/rector-phpunit Extensions