How can I ensure Laravel's after() callback runs only when rules() validation passes?

In Laravel the callbacks returned by the Form Request's after method are always executed after the primary validation rules—even if the primary rules failed. This means that if, for example, "user_number" is empty (failing the "required" rule), the after callbacks will still run.

To conditionally run your additional checks only when the primary rules pass, you can check whether the validator already has errors and return early from the callback. For example:

PHPCopied
use Illuminate\Validation\Validator;

class UpdateUserRequest extends FormRequest
{
    public function authorize(): bool
    {
        return true;
    }

    public function rules(): array
    {
        return [
            "first_name"  => "required",
            "last_name"   => "required",
            "user_number" => "required|exists:users,user_number",
        ];
    }

    public function after(): array
    {
        return [
            function (Validator $validator) {
                // If there are existing errors, skip further checks
                if ($validator->errors()->isNotEmpty()) {
                    return;
                }

                // Only reached if primary validation passed
                $user = User::whereUserNumber($this->user_number)->first();

                // Perform additional checks
                if ($this->somethingElseIsInvalid($user)) {
                    $validator->errors()->add('user_number', 'Additional error message.');
                }
            }
        ];
    }

    protected function somethingElseIsInvalid($user): bool
    {
        // Additional domain-specific logic...
        return false;
    }
}

Explanation

• Validation Flow:
  Primary validation (from the rules method) runs first.
• Checking for Errors:
  Within the after callback, checking if $validator->errors()->isNotEmpty() ensures that if any rule fails (like "user_number" being empty), the additional logic is skipped.
• Additional Checks:
  If there are no errors, the code proceeds to query the user and perform the extra business logic.

This approach elegantly separates the base validation logic from the additional checks and ensures the extra validations are only applied when the primary rules pass.