Prevent Null Pointer Errors with withDefault() Relationships

Attach withDefault() to belongsTo, hasOne, and morphOne relationships to return a blank or pre-populated model instance when the relation is null.

When a relationship is optional (such as a Post having an optional Author, or an Order having an optional PromoCode), accessing attributes directly ($post->author->name) can throw an Attempt to read property on null error if the relation is unset.

Using withDefault() returns an empty model instance instead of null.

Basic Default Model

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

class Post extends Model
{
    public function author(): BelongsTo
    {
        return $this->belongsTo(User::class, 'user_id')->withDefault();
    }
}

When $post->user_id is null, $post->author returns a blank User instance where properties evaluate to null instead of throwing an error:

// Returns null without throwing an exception
echo $post->author->name;

Providing Default Attribute Values

You can pass an array of fallback values or a closure to pre-populate default attributes:

public function author(): BelongsTo
{
    return $this->belongsTo(User::class, 'user_id')->withDefault([
        'name' => 'Guest Author',
        'email' => '[email protected]',
    ]);
}

Summary

• Protects views and services from Attempt to read property on null exceptions.
• Keeps Blade views clean by removing repetitive $post->author?->name ?? 'Guest' ternary operators.
• Applicable to belongsTo, hasOne, hasOneThrough, and morphOne relations.