Extending parent rules in child form requests

To add fields in a child, use the spread operator: return [...parent::rules(), 'extra' => FluentRule::string()->required()]. If you need to modify a parent's rule, clone it first since ->rule() mutates the object: $rules['type'] = (clone $rules['type'])->rule(new ExtraRule()).

When the parent defines a keyed each([...]) or children([...]) map and the child needs to add or replace one sub-rule, use the extend helpers on ArrayRule / FieldRule via RuleSet::modify, or reach for the modifyEach / modifyChildren sugar:

php

// Parent
return RuleSet::from([
    'answers' => FluentRule::array()->nullable()->max(20)->each([
        'text' => FluentRule::string()->required(),
    ]),
]);

// Child, sugar form (later-wins merge)
return parent::rules()->modifyEach('answers', [
    'id' => FluentRule::numeric()->nullable(),
]);

// Or the strict-add primitive; throws on existing-key collision
return parent::rules()->modify('answers', fn (ArrayRule $rule) =>
    $rule->addEachRule('id', FluentRule::numeric()->nullable())
);

modifyEach wraps mergeEachRules (later-wins on collision); modifyChildren wraps mergeChildRules on FieldRule. For strict add-only semantics, use the primitive modify(..., fn ($r) => $r->addEachRule(...)). addEachRule / addChildRule throw on existing-key collision. Base constraints (nullable, max:20, etc.) are preserved by design.

rules() may also return a RuleSet directly; HasFluentRules (and HasFluentValidation for Livewire) auto-unwrap it via ->toArray() before passing to the validator. This lets you chain ->only/->except/->merge/->put/->get and return without a terminal ->toArray() call:

php

// Assumes a class-level helper that returns a RuleSet, e.g.
//   class UserRules { public static function base(): RuleSet { return RuleSet::from([...]); } }
public function rules(): RuleSet
{
    return UserRules::base()
        ->only(['email', 'password'])
        ->put('email_confirmation', FluentRule::email()->required()->same('email'));
}

RuleSet also implements IteratorAggregate, so spread works on it too: [...$ruleSet, 'extra' => FluentRule::string()->required()].

Extending parent rules in child form requests ​

Extending parent rules in child form requests