[12.x] fix: Models having inconsistent guarding behaviour (#56381)

* bug: adding unittest for guarded models

Adding a unit test to cover edge cases where models exhibit inconsistent
behaviour when the $guard property is empty but the $fillable is not.
A MassAssignmentException is thrown. this happens because getGuarded in
GuardsAttributes has two different mechanisms for unguarding a model.

1. $unguarded boolean property (default: false)
2. $guarded array property (default: ['*'])

`getGuarded()` uses the $guarded and checks if it's false to return and
empty array.

`fillableFromArray()` uses $unguarded and $fillable properties to test if the model is unguarded.

Both methods should use $unguarded for consistent behaviour.

* bug: changing getGuarded to use $unguarded

* feat: updatinng docblock

Author: JimTools

src/Illuminate/Database/Eloquent/Concerns/GuardsAttributes.php

@@ -14,7 +14,7 @@ trait GuardsAttributes
     /**
      * The attributes that aren't mass assignable.
      *
-     * @var array<string>|bool
+     * @var array<string>
      */
     protected $guarded = ['*'];
 
@@ -28,7 +28,7 @@ trait GuardsAttributes
     /**
      * The actual columns that exist on the database and can be guarded.
      *
-     * @var array<string>
+     * @var array<class-string,list<string>>
      */
     protected static $guardableColumns = [];
 
@@ -75,7 +75,7 @@ public function mergeFillable(array $fillable)
      */
     public function getGuarded()
     {
-        return $this->guarded === false
+        return self::$unguarded === true
             ? []
             : $this->guarded;
     }

tests/Database/DatabaseEloquentModelTest.php

@@ -10,7 +10,6 @@
 use Illuminate\Contracts\Database\Eloquent\Castable;
 use Illuminate\Contracts\Database\Eloquent\CastsAttributes;
 use Illuminate\Contracts\Database\Eloquent\CastsInboundAttributes;
-use Illuminate\Contracts\Encryption\Encrypter;
 use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Database\Connection;
 use Illuminate\Database\ConnectionResolverInterface;
@@ -47,7 +46,6 @@
 use Illuminate\Database\Query\Processors\Processor;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Collection as BaseCollection;
-use Illuminate\Support\Facades\Crypt;
 use Illuminate\Support\Fluent;
 use Illuminate\Support\HtmlString;
 use Illuminate\Support\InteractsWithTime;
@@ -1704,6 +1702,27 @@ public function testGuarded()
         Model::preventSilentlyDiscardingAttributes(false);
     }
 
+    public function testGuardedWithFillableConfig(): void
+    {
+        $model = new EloquentModelStub;
+        $model::unguard();
+
+        EloquentModelStub::setConnectionResolver($resolver = m::mock(Resolver::class));
+        $resolver->shouldReceive('connection')->andReturn($connection = m::mock(stdClass::class));
+        $connection->shouldReceive('getSchemaBuilder->getColumnListing')->andReturn(['name', 'age', 'foo']);
+
+        $model->guard([]);
+        $model->fillable(['name']);
+        $model->fill(['name' => 'Leto Atreides', 'age' => 51]);
+
+        self::assertSame(
+            ['name' => 'Leto Atreides', 'age' => 51],
+            $model->getAttributes(),
+        );
+
+        $model::reguard();
+    }
+
     public function testUsesOverriddenHandlerWhenDiscardingAttributes()
     {
         EloquentModelStub::setConnectionResolver($resolver = m::mock(Resolver::class));