[12.x] Adds set relation attribute using Model.

Author: DarkGhostHunter

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

@@ -8,6 +8,7 @@
 use Brick\Math\RoundingMode;
 use Carbon\CarbonImmutable;
 use Carbon\CarbonInterface;
+use Closure;
 use DateTimeImmutable;
 use DateTimeInterface;
 use Illuminate\Contracts\Database\Eloquent\Castable;
@@ -24,6 +25,8 @@
 use Illuminate\Database\Eloquent\InvalidCastException;
 use Illuminate\Database\Eloquent\JsonEncodingException;
 use Illuminate\Database\Eloquent\MissingAttributeException;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\Relation;
 use Illuminate\Database\LazyLoadingViolationException;
 use Illuminate\Support\Arr;
@@ -581,6 +584,32 @@ public function isRelation($key)
                $this->relationResolver(static::class, $key);
     }
 
+    /**
+     * Determine if the given relation name is a BelongsTo relation.
+     *
+     * @param  string  $key
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function isBelongsToRelation($key, $value)
+    {
+        return $value instanceof Model
+            && $this->isRelation($key)
+            && $this->{$key}() instanceof BelongsTo;
+    }
+
+    /**
+     * Associates or attaches a model relation using the appropriate method relation.
+     *
+     * @param  string  $relation
+     * @param  \Illuminate\Database\Eloquent\Model  $instance
+     * @return $this
+     */
+    protected function fillBelongsToRelation($relation, $instance)
+    {
+        return $this->$relation()->associate($instance);
+    }
+
     /**
      * Handle a lazy loading violation.
      *
@@ -1074,6 +1103,10 @@ public function setAttribute($key, $value)
             $value = $this->castAttributeAsHashedString($key, $value);
         }
 
+        if ($this->isBelongsToRelation($key, $value)) {
+            return $this->fillBelongsToRelation($key, $value);
+        }
+
         $this->attributes[$key] = $value;
 
         return $this;

tests/Database/DatabaseEloquentModelTest.php

@@ -1575,6 +1575,55 @@ public function testFillable()
         $this->assertSame('bar', $model->age);
     }
 
+    public function testFillableWithBelongsToRelation()
+    {
+        $model = new EloquentModelStub;
+        $this->addMockConnection($model);
+
+        $model->fillable(['name', 'age']);
+        $relation = new EloquentModelSaveStub();
+        $relation->id = 10;
+
+        $model->fill(['name' => 'foo', 'age' => 'bar', 'belongsToStub' => $relation, 'morphToStub' => $relation]);
+
+        $this->assertNull($model->belongs_to_stub_id);
+        $this->assertNull($model->morph_to_stub_id);
+
+        $model->fillable(['name', 'age', 'belongsToStub', 'morphToStub']);
+        $model->fill(['name' => 'foo', 'age' => 'bar', 'belongsToStub' => $relation, 'morphToStub' => $relation]);
+
+        $this->assertSame('foo', $model->name);
+        $this->assertSame('bar', $model->age);
+        $this->assertSame(10, $model->belongs_to_stub_id);
+        $this->assertSame(10, $model->morph_to_stub_id);
+        $this->assertSame(EloquentModelSaveStub::class, $model->morph_to_stub_type);
+        $this->assertSAme($relation, $model->getRelation('belongsToStub'));
+        $this->assertSAme($relation, $model->getRelation('morphToStub'));
+
+        $this->assertSame('foo', $model->fill(['belongsToStub' => 'foo'])->belongsToStub);
+    }
+
+    public function testFillableWithBelongsToRelationNotFillable()
+    {
+        $model = new EloquentModelStub;
+        $model->fillable(['name', 'age', 'belongsToStub']);
+
+        $model->fill(['belongsToStub' => 'foo']);
+
+        $this->assertNull($model->foo);
+
+        $model = new EloquentModelWithWhereHasStub;
+        $this->addMockConnection($model);
+        $model->fillable(['name', 'foo']);
+
+        $relation = new EloquentModelSaveStub();
+
+        $model->fill(['foo' => $relation]);
+
+        $this->assertNull($model->getRelation('foo'));
+        $this->assertSame($relation, $model->getAttribute('foo'));
+    }
+
     public function testQualifyColumn()
     {
         $model = new EloquentModelStub;