[12.x] Preserve "previous" model state (#55729)

* Preserve previous model state

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

* Update EloquentModelRefreshTest.php

* wip

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

* wip

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

* Update HasAttributes.php

* Update HasAttributes.php

---------

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>
Co-authored-by: Taylor Otwell <taylor@laravel.com>

Author: crynobone

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

@@ -68,6 +68,13 @@ trait HasAttributes
      */
     protected $changes = [];
 
+    /**
+     * The previous state of the changed model attributes.
+     *
+     * @var array
+     */
+    protected $previous = [];
+
     /**
      * The attributes that should be cast.
      *
@@ -2082,6 +2089,7 @@ public function syncOriginalAttributes($attributes)
     public function syncChanges()
     {
         $this->changes = $this->getDirty();
+        $this->previous = array_intersect_key($this->getRawOriginal(), $this->changes);
 
         return $this;
     }
@@ -2117,7 +2125,7 @@ public function isClean($attributes = null)
      */
     public function discardChanges()
     {
-        [$this->attributes, $this->changes] = [$this->original, []];
+        [$this->attributes, $this->changes, $this->previous] = [$this->original, [], []];
 
         return $this;
     }
@@ -2201,6 +2209,16 @@ public function getChanges()
         return $this->changes;
     }
 
+    /**
+     * Get the attributes that were previously original before the model was last saved.
+     *
+     * @return array
+     */
+    public function getPrevious()
+    {
+        return $this->previous;
+    }
+
     /**
      * Determine if the new and old values for a given key are equivalent.
      *

tests/Integration/Database/EloquentModelRefreshTest.php

@@ -54,6 +54,18 @@ public function testItSyncsOriginalOnRefresh()
         $this->assertSame('patrick', $post->getOriginal('title'));
     }
 
+    public function testItDoesNotSyncPreviousOnRefresh()
+    {
+        $post = Post::create(['title' => 'pat']);
+
+        Post::find($post->id)->update(['title' => 'patrick']);
+
+        $post->refresh();
+
+        $this->assertEmpty($post->getDirty());
+        $this->assertEmpty($post->getPrevious());
+    }
+
     public function testAsPivot()
     {
         Schema::create('post_posts', function (Blueprint $table) {

tests/Integration/Database/EloquentModelTest.php

@@ -42,25 +42,28 @@ public function testUserCanUpdateNullableDate()
     public function testAttributeChanges()
     {
         $user = TestModel2::create([
-            'name' => Str::random(), 'title' => Str::random(),
+            'name' => $originalName = Str::random(), 'title' => Str::random(),
         ]);
 
         $this->assertEmpty($user->getDirty());
         $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
         $this->assertFalse($user->isDirty());
         $this->assertFalse($user->wasChanged());
 
-        $user->name = $name = Str::random();
+        $user->name = $overrideName = Str::random();
 
-        $this->assertEquals(['name' => $name], $user->getDirty());
+        $this->assertEquals(['name' => $overrideName], $user->getDirty());
         $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
         $this->assertTrue($user->isDirty());
         $this->assertFalse($user->wasChanged());
 
         $user->save();
 
         $this->assertEmpty($user->getDirty());
-        $this->assertEquals(['name' => $name], $user->getChanges());
+        $this->assertEquals(['name' => $overrideName], $user->getChanges());
+        $this->assertEquals(['name' => $originalName], $user->getPrevious());
         $this->assertTrue($user->wasChanged());
         $this->assertTrue($user->wasChanged('name'));
     }
@@ -73,13 +76,15 @@ public function testDiscardChanges()
 
         $this->assertEmpty($user->getDirty());
         $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
         $this->assertFalse($user->isDirty());
         $this->assertFalse($user->wasChanged());
 
         $user->name = $overrideName = Str::random();
 
         $this->assertEquals(['name' => $overrideName], $user->getDirty());
         $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
         $this->assertTrue($user->isDirty());
         $this->assertFalse($user->wasChanged());
         $this->assertSame($originalName, $user->getOriginal('name'));
@@ -88,11 +93,15 @@ public function testDiscardChanges()
         $user->discardChanges();
 
         $this->assertEmpty($user->getDirty());
+        $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
         $this->assertSame($originalName, $user->getOriginal('name'));
         $this->assertSame($originalName, $user->getAttribute('name'));
 
         $user->save();
         $this->assertFalse($user->wasChanged());
+        $this->assertEmpty($user->getChanges());
+        $this->assertEmpty($user->getPrevious());
     }
 
     public function testInsertRecordWithReservedWordFieldName()

tests/Integration/Database/EloquentUpdateTest.php

@@ -136,6 +136,50 @@ public function testIncrementOrDecrementIgnoresGlobalScopes()
         $deletedModel->decrement('counter');
         $this->assertEquals(0, $deletedModel->fresh()->counter);
     }
+
+    public function testUpdateSyncsPrevious()
+    {
+        $model = TestUpdateModel1::create([
+            'name' => Str::random(),
+            'title' => 'Ms.',
+        ]);
+
+        $model->update(['title' => 'Dr.']);
+
+        $this->assertSame('Dr.', $model->title);
+        $this->assertSame('Dr.', $model->getOriginal('title'));
+        $this->assertSame(['title' => 'Dr.'], $model->getChanges());
+        $this->assertSame(['title' => 'Ms.'], $model->getPrevious());
+    }
+
+    public function testSaveSyncsPrevious()
+    {
+        $model = TestUpdateModel1::create([
+            'name' => Str::random(),
+            'title' => 'Ms.',
+        ]);
+
+        $model->title = 'Dr.';
+        $model->save();
+
+        $this->assertSame('Dr.', $model->title);
+        $this->assertSame('Dr.', $model->getOriginal('title'));
+        $this->assertSame(['title' => 'Dr.'], $model->getChanges());
+        $this->assertSame(['title' => 'Ms.'], $model->getPrevious());
+    }
+
+    public function testIncrementSyncsPrevious()
+    {
+        $model = TestUpdateModel3::create([
+            'counter' => 0,
+        ]);
+
+        $model->increment('counter');
+
+        $this->assertEquals(1, $model->counter);
+        $this->assertSame(['counter' => 1], $model->getChanges());
+        $this->assertSame(['counter' => 0], $model->getPrevious());
+    }
 }
 
 class TestUpdateModel1 extends Model