dhpk-php-modern-pro

PHP modern pro — 7.4 baseline + dual-floor library design

This skill is the counterpart to dhpk-php-runtime-router (which assumes PHP 5.6 and forbids ≥7.0 syntax). Load it when working on code that targets PHP 7.4 or a library that intentionally spans 7.x→8.x.

modules/php-7.4/references/static-checks.md is the always-loaded index into the tooling tier (php-cs-fixer + phpstan/psalm). This skill is the language & packaging companion — load when designing API shape, picking idioms, or reviewing composer constraints.

Rule of thumb: dhpk-php-runtime-router is for legacy monoliths frozen at 5.6. dhpk-php-modern-pro is for greenfield 7.4+ code and any composer package that ships against a version range.

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7.4 baseline — prefer these idioms

Typed properties

final class UserId
{
    private int $value;

    public function __construct(int $value)
    {
        $this->value = $value;
    }
}

• Always type properties. Drop PHPDoc @var once the property is typed unless the type is a narrowed version of the declared type (e.g. array<string, User> on top of array).
• Prefer final on value objects and on classes that aren't designed for inheritance. Subclasses you can't anticipate are subclasses you'll regret.

Arrow functions

$ids = array_map(fn(User $u): int => $u->id(), $users);

• Use for one-expression callbacks. They auto-capture by value.
• Don't reach for function (…) use (…) {} unless you need a multi-line body. Arrow fns make array_* and Collection::map/filter callsites read top-to-bottom.

Null-coalesce assignment

$config['timeout'] ??= 30;

• Replaces $config['timeout'] = $config['timeout'] ?? 30;.
• Works on array offsets, object properties, and plain variables.

Spread in arrays

$base = ['a', 'b'];
$all  = [...$base, 'c', 'd'];

• Replaces array_merge for plain numeric arrays. Not safe for string-keyed arrays in 7.4 — string keys throw; only numeric keys spread. (PHP 8.1+ lifts this restriction.)