Correct implementation of float casting comparison (#33322)

Author: GrahamCampbell

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

@@ -1178,6 +1178,8 @@ public function originalIsEquivalent($key, $current)
         } elseif ($this->hasCast($key, ['object', 'collection'])) {
             return $this->castAttribute($key, $current) ==
                 $this->castAttribute($key, $original);
+        } elseif ($this->hasCast($key, ['real', 'float', 'double'])) {
+            return abs($this->castAttribute($key, $current) - $this->castAttribute($key, $original)) < PHP_FLOAT_EPSILON * 4;
         } elseif ($this->hasCast($key)) {
             return $this->castAttribute($key, $current) ===
                    $this->castAttribute($key, $original);

tests/Database/DatabaseEloquentModelTest.php

@@ -148,6 +148,19 @@ public function testCleanAttributes()
         $this->assertFalse($model->isClean(['foo', 'bar']));
     }
 
+    public function testCleanWhenFloatUpdateAttribute()
+    {
+        // test is equivalent
+        $model = new EloquentModelStub(['castedFloat' => 8 - 6.4]);
+        $model->syncOriginal();
+        $this->assertTrue($model->originalIsEquivalent('castedFloat', 1.6));
+
+        // test is not equivalent
+        $model = new EloquentModelStub(['castedFloat' => 5.6]);
+        $model->syncOriginal();
+        $this->assertFalse($model->originalIsEquivalent('castedFloat', 5.5));
+    }
+
     public function testCalculatedAttributes()
     {
         $model = new EloquentModelStub;
@@ -1992,6 +2005,7 @@ class EloquentModelStub extends Model
     protected $table = 'stub';
     protected $guarded = [];
     protected $morph_to_stub_type = EloquentModelSaveStub::class;
+    protected $casts = ['castedFloat' => 'float'];
 
     public function getListItemsAttribute($value)
     {