Fix PHP warnings when opening Page Break modal in article view

Author: sathwikre

administrator/components/com_content/src/View/Article/HtmlView.php

@@ -104,7 +104,11 @@ public function display($tpl = null)
         $this->form  = $model->getForm();
         $this->item  = $model->getItem();
         $this->state = $model->getState();
-        $this->canDo = ContentHelper::getActions('com_content', 'article', $this->item->id);
+        $this->canDo = ContentHelper::getActions(
+            'com_content',
+            'article',
+            $this->item ? (int) $this->item->id : 0
+        );
 
         if ($this->getLayout() === 'modalreturn') {
             parent::display($tpl);
@@ -157,8 +161,10 @@ protected function addToolbar()
         Factory::getApplication()->getInput()->set('hidemainmenu', true);
         $user       = $this->getCurrentUser();
         $userId     = $user->id;
-        $isNew      = ($this->item->id == 0);
-        $checkedOut = !(\is_null($this->item->checked_out) || $this->item->checked_out == $userId);
+        $isNew      = empty($this->item) || empty($this->item->id);
+        $checkedOut = !empty($this->item)
+            && !\is_null($this->item->checked_out)
+            && $this->item->checked_out != $userId;
         $toolbar    = $this->getDocument()->getToolbar();
 
         // Built the actions for new and existing records.
@@ -267,8 +273,10 @@ protected function addModalToolbar()
     {
         $user       = $this->getCurrentUser();
         $userId     = $user->id;
-        $isNew      = ($this->item->id == 0);
-        $checkedOut = !(\is_null($this->item->checked_out) || $this->item->checked_out == $userId);
+        $isNew      = empty($this->item) || empty($this->item->id);
+        $checkedOut = !empty($this->item)
+            && !\is_null($this->item->checked_out)
+            && $this->item->checked_out != $userId;
         $toolbar    = $this->getDocument()->getToolbar();
 
         // Build the actions for new and existing records.