Fix Framework\Data\Collection::each() method

lib/internal/Magento/Framework/Data/Collection.php

@@ -515,17 +515,29 @@ public function walk($callback, array $args = [])
     }
 
     /**
-     * @param string|array $objMethod
+     * Call method or callback on each item in the collection.
+     * 
+     * @param string|array|\Closure $objMethod
      * @param array $args
      * @return void
      */
     public function each($objMethod, $args = [])
     {
-        foreach ($args->_items as $k => $item) {
-            $args->_items[$k] = call_user_func($objMethod, $item);
+        if ($objMethod instanceof \Closure) {
+            foreach ($this->getItems() as $item) {
+                $objMethod($item, ...$args);
+            }
+        } elseif (is_array($objMethod)) {
+            foreach ($this->getItems() as $item) {
+                call_user_func($objMethod, $item, ...$args);
+            }
+        } else {
+            foreach ($this->getItems() as $item) {
+                $item->$objMethod(...$args);
+            }
         }
     }
-
+    
     /**
      * Setting data for all collection items
      *

lib/internal/Magento/Framework/Data/Test/Unit/CollectionTest.php

@@ -173,4 +173,85 @@ public function testPossibleFlowWithItem()
         $this->_model->removeAllItems();
         $this->assertEquals([], $this->_model->getItems());
     }
+
+    public function testEachCallsMethodOnEachItemWithNoArgs()
+    {
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testCallback']);
+            $item->expects($this->once())->method('testCallback')->with();
+            $this->_model->addItem($item);
+        }
+        $this->_model->each('testCallback');
+    }
+
+    public function testEachCallsMethodOnEachItemWithArgs()
+    {
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testCallback']);
+            $item->expects($this->once())->method('testCallback')->with('a', 'b', 'c');
+            $this->_model->addItem($item);
+        }
+        $this->_model->each('testCallback', ['a', 'b', 'c']);
+    }
+
+    public function testCallsClosureWithEachItemAndNoArgs()
+    {
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testCallback']);
+            $item->expects($this->once())->method('testCallback')->with();
+            $this->_model->addItem($item);
+        }
+        $this->_model->each(function ($item) {
+            $item->testCallback();
+        });
+    }
+
+    public function testCallsClosureWithEachItemAndArgs()
+    {
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testItemCallback']);
+            $item->expects($this->once())->method('testItemCallback')->with('a', 'b', 'c');
+            $this->_model->addItem($item);
+        }
+        $this->_model->each(function ($item, ...$args) {
+            $item->testItemCallback(...$args);
+        }, ['a', 'b', 'c']);
+    }
+
+    public function testCallsCallableArrayWithEachItemNoArgs()
+    {
+        $mockCallbackObject = $this->getMockBuilder('DummyEachCallbackInstance')
+            ->setMethods(['testObjCallback'])
+            ->getMock();
+        $mockCallbackObject->method('testObjCallback')->willReturnCallback(function ($item, ...$args) {
+            $item->testItemCallback(...$args);
+        });
+
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testItemCallback']);
+            $item->expects($this->once())->method('testItemCallback')->with();
+            $this->_model->addItem($item);
+        }
+
+        $this->_model->each([$mockCallbackObject, 'testObjCallback']);
+    }
+
+    public function testCallsCallableArrayWithEachItemAndArgs()
+    {
+        $mockCallbackObject = $this->getMockBuilder('DummyEachCallbackInstance')
+            ->setMethods(['testObjCallback'])
+            ->getMock();
+        $mockCallbackObject->method('testObjCallback')->willReturnCallback(function ($item, ...$args) {
+            $item->testItemCallback(...$args);
+        });
+
+        for ($i = 0; $i < 3; $i++) {
+            $item = $this->getMock(\Magento\Framework\DataObject::class, ['testItemCallback']);
+            $item->expects($this->once())->method('testItemCallback')->with('a', 'b', 'c');
+            $this->_model->addItem($item);
+        }
+
+        $callback = [$mockCallbackObject, 'testObjCallback'];
+        $this->_model->each($callback, ['a', 'b', 'c']);
+    }
 }