Rector — Automated PHP Upgrades & Refactoring

Also Known As

TL;DR

Explanation

Rector (Reconstruct, Refactor) uses PHP-Parser to build an AST, applies transformation rules, and rewrites the source files. Primary uses: automated PHP version upgrades (replace deprecated functions, add typed properties, convert to match expressions, add return types), framework migrations (Symfony 4→5→6, Laravel upgrades, PHPUnit version migrations), and custom rule sets for enforcing architectural patterns. Run rector process --dry-run to preview changes; rector process to apply them. Commit Rector output as a separate commit for clean diffs. Write custom Rector rules to automate project-specific refactors — extracting a recurring pattern into a method or renaming a class across the codebase. Pair with PHPStan to validate the output is type-correct.

Common Misconception

Why It Matters

Common Mistakes

• Running Rector on the whole codebase without reviewing changes — automated changes can be wrong.
• Not committing before running Rector — no clean rollback if a rule causes issues.
• Using only the 'upgrade' rule set and ignoring code quality rules that reduce complexity.
• Not creating a custom Rector rule for project-specific repetitive refactors.

Code Examples

# Running Rector without review — risky:
rector process src/ --no-diffs  # Applies changes silently

# Safe workflow:
git stash  # Clean state
rector process src/ --dry-run   # Preview changes
# Review output, adjust rector.php rules
rector process src/             # Apply after review
git diff                        # Review all changes before committing

// Rector — automated PHP refactoring and upgrades

// Install:
$ composer require --dev rector/rector

// rector.php config
use Rector\Config\RectorConfig;
use Rector\Set\ValueObject\SetList;
use Rector\Set\ValueObject\LevelSetList;

return RectorConfig::configure()
    ->withPaths([__DIR__ . '/src', __DIR__ . '/tests'])
    ->withSets([
        LevelSetList::UP_TO_PHP_83,          // upgrade deprecated syntax
        SetList::DEAD_CODE,                   // remove dead code
        SetList::CODE_QUALITY,                // simplify expressions
        SetList::TYPE_DECLARATION,            // add missing type hints
    ]);

// Dry run first:
$ vendor/bin/rector process --dry-run

// Apply:
$ vendor/bin/rector process
$ composer test  // verify nothing broke

References

• ↗ https://getrector.com/documentation

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