Fixed clear cache for item page
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index 95d9385..57b7599 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -39,3 +39,4 @@
execute:frappe.delete_doc("DocType", "Grade")
erpnext.patches.4_0.remove_india_specific_fields
execute:frappe.delete_doc_if_exists("DocType", "Warehouse User")
+execute:frappe.db.sql("delete from `tabWebsite Item Group` where ifnull(item_group, '')=''")
diff --git a/erpnext/stock/doctype/item/item.py b/erpnext/stock/doctype/item/item.py
index c4ca77f..9b2d862 100644
--- a/erpnext/stock/doctype/item/item.py
+++ b/erpnext/stock/doctype/item/item.py
@@ -348,4 +348,5 @@
def invalidate_cache_for_item(doc):
invalidate_cache_for(doc, doc.item_group)
for d in doc.get({"doctype":"Website Item Group"}):
- invalidate_cache_for(doc, d.item_group)
+ if d.item_group:
+ invalidate_cache_for(doc, d.item_group)