Fixed set template syntax issue

Author: sanganinamrata

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Composite/Fieldset/Options/Type/Checkbox.php

@@ -15,7 +15,7 @@ class Checkbox extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Op
     /**
      * @var string
      */
-    protected $_template = 'product/composite/fieldset/options/type/checkbox.phtml';
+    protected $_template = 'Magento_Bundle::product/composite/fieldset/options/type/checkbox.phtml';
 
     /**
      * @param  string $elementId

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Composite/Fieldset/Options/Type/Multi.php

@@ -15,7 +15,7 @@ class Multi extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Optio
     /**
      * @var string
      */
-    protected $_template = 'product/composite/fieldset/options/type/multi.phtml';
+    protected $_template = 'Magento_Bundle::product/composite/fieldset/options/type/multi.phtml';
 
     /**
      * @param  string $elementId

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Composite/Fieldset/Options/Type/Radio.php

@@ -15,7 +15,7 @@ class Radio extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Optio
     /**
      * @var string
      */
-    protected $_template = 'product/composite/fieldset/options/type/radio.phtml';
+    protected $_template = 'Magento_Bundle::product/composite/fieldset/options/type/radio.phtml';
 
     /**
      * @param  string $elementId

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Composite/Fieldset/Options/Type/Select.php

@@ -15,7 +15,7 @@ class Select extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Opti
     /**
      * @var string
      */
-    protected $_template = 'product/composite/fieldset/options/type/select.phtml';
+    protected $_template = 'Magento_Bundle::product/composite/fieldset/options/type/select.phtml';
 
     /**
      * @param  string $elementId

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Edit/Tab/Bundle.php

@@ -20,7 +20,7 @@ class Bundle extends \Magento\Backend\Block\Widget implements \Magento\Backend\B
     /**
      * @var string
      */
-    protected $_template = 'product/edit/bundle.phtml';
+    protected $_template = 'Magento_Bundle::product/edit/bundle.phtml';
 
     /**
      * Core registry

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Edit/Tab/Bundle/Option.php

@@ -26,7 +26,7 @@ class Option extends \Magento\Backend\Block\Widget
     /**
      * @var string
      */
-    protected $_template = 'product/edit/bundle/option.phtml';
+    protected $_template = 'Magento_Bundle::product/edit/bundle/option.phtml';
 
     /**
      * Core registry

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Edit/Tab/Bundle/Option/Search.php

@@ -15,7 +15,7 @@ class Search extends \Magento\Backend\Block\Widget
     /**
      * @var string
      */
-    protected $_template = 'product/edit/bundle/option/search.phtml';
+    protected $_template = 'Magento_Bundle::product/edit/bundle/option/search.phtml';
 
     /**
      * @return void

app/code/Magento/Bundle/Block/Adminhtml/Catalog/Product/Edit/Tab/Bundle/Option/Selection.php

@@ -15,7 +15,7 @@ class Selection extends \Magento\Backend\Block\Widget
     /**
      * @var string
      */
-    protected $_template = 'product/edit/bundle/option/selection.phtml';
+    protected $_template = 'Magento_Bundle::product/edit/bundle/option/selection.phtml';
 
     /**
      * Catalog data

app/code/Magento/Bundle/Block/Catalog/Product/View/Type/Bundle/Option/Checkbox.php

@@ -15,5 +15,5 @@ class Checkbox extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Op
     /**
      * @var string
      */
-    protected $_template = 'catalog/product/view/type/bundle/option/checkbox.phtml';
+    protected $_template = 'Magento_Bundle::catalog/product/view/type/bundle/option/checkbox.phtml';
 }

app/code/Magento/Bundle/Block/Catalog/Product/View/Type/Bundle/Option/Multi.php

@@ -15,5 +15,22 @@ class Multi extends \Magento\Bundle\Block\Catalog\Product\View\Type\Bundle\Optio
     /**
      * @var string
      */
-    protected $_template = 'catalog/product/view/type/bundle/option/multi.phtml';
+    protected $_template = 'Magento_Bundle::catalog/product/view/type/bundle/option/multi.phtml';
+
+    /**
+     * @inheritdoc
+     * @since 100.2.0
+     */
+    protected function assignSelection(\Magento\Bundle\Model\Option $option, $selectionId)
+    {
+        if (is_array($selectionId)) {
+            foreach ($selectionId as $id) {
+                if ($id && $option->getSelectionById($id)) {
+                    $this->_selectedOptions[] = $id;
+                }
+            }
+        } else {
+            parent::assignSelection($option, $selectionId);
+        }
+    }
 }