Public mutable field (ARCH7186)

Key php.quality.public-mutable-field · Severity warning · Category quality

Public mutable fields break encapsulation and allow uncontrolled external mutation. Hide the field and expose it through guarded methods.

Incorrect

<?php
class Account
{
    public float $balance = 0.0;
}

Correct

<?php
class Account
{
    private float $balance = 0.0;

    public function deposit(float $amount): void
    {
        if ($amount <= 0) throw new InvalidArgumentException('positive only');
        $this->balance += $amount;
    }

    public function balance(): float
    {
        return $this->balance;
    }
}

Fix

Make the field private and expose access through validating getter/mutator methods.