[Enhancement] Sales and Purchase Default UOM (#10929)

Option for specifying an optional default Sales and Purchase UOM at the item master level.
diff --git a/erpnext/stock/doctype/item/item.json b/erpnext/stock/doctype/item/item.json
index b168631..525321c 100644
--- a/erpnext/stock/doctype/item/item.json
+++ b/erpnext/stock/doctype/item/item.json
@@ -1479,6 +1479,37 @@
    "bold": 0, 
    "collapsible": 0, 
    "columns": 0, 
+   "fieldname": "purchase_uom", 
+   "fieldtype": "Link", 
+   "hidden": 0, 
+   "ignore_user_permissions": 0, 
+   "ignore_xss_filter": 0, 
+   "in_filter": 0, 
+   "in_global_search": 0, 
+   "in_list_view": 0, 
+   "in_standard_filter": 0, 
+   "label": "Default Purchase Unit of Measure", 
+   "length": 0, 
+   "no_copy": 0, 
+   "options": "UOM", 
+   "permlevel": 0, 
+   "precision": "", 
+   "print_hide": 0, 
+   "print_hide_if_no_value": 0, 
+   "read_only": 0, 
+   "remember_last_selected_value": 0, 
+   "report_hide": 0, 
+   "reqd": 0, 
+   "search_index": 0, 
+   "set_only_once": 0, 
+   "unique": 0
+  }, 
+  {
+   "allow_bulk_edit": 0, 
+   "allow_on_submit": 0, 
+   "bold": 0, 
+   "collapsible": 0, 
+   "columns": 0, 
    "default": "0.00", 
    "depends_on": "is_stock_item", 
    "description": "", 
@@ -2075,6 +2106,37 @@
    "bold": 0, 
    "collapsible": 0, 
    "columns": 0, 
+   "fieldname": "sales_uom", 
+   "fieldtype": "Link", 
+   "hidden": 0, 
+   "ignore_user_permissions": 0, 
+   "ignore_xss_filter": 0, 
+   "in_filter": 0, 
+   "in_global_search": 0, 
+   "in_list_view": 0, 
+   "in_standard_filter": 0, 
+   "label": "Default Sales Unit of Measure", 
+   "length": 0, 
+   "no_copy": 0, 
+   "options": "UOM", 
+   "permlevel": 0, 
+   "precision": "", 
+   "print_hide": 0, 
+   "print_hide_if_no_value": 0, 
+   "read_only": 0, 
+   "remember_last_selected_value": 0, 
+   "report_hide": 0, 
+   "reqd": 0, 
+   "search_index": 0, 
+   "set_only_once": 0, 
+   "unique": 0
+  }, 
+  {
+   "allow_bulk_edit": 0, 
+   "allow_on_submit": 0, 
+   "bold": 0, 
+   "collapsible": 0, 
+   "columns": 0, 
    "default": "0", 
    "description": "Publish Item to hub.erpnext.com", 
    "fieldname": "publish_in_hub", 
@@ -3143,7 +3205,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 1, 
- "modified": "2017-07-06 18:28:36.645217", 
+ "modified": "2017-09-27 14:08:02.948326", 
  "modified_by": "Administrator", 
  "module": "Stock", 
  "name": "Item", 
diff --git a/erpnext/stock/get_item_details.py b/erpnext/stock/get_item_details.py
index 72a83c6..0b92c25 100644
--- a/erpnext/stock/get_item_details.py
+++ b/erpnext/stock/get_item_details.py
@@ -164,6 +164,16 @@
 
 	warehouse = user_default_warehouse or item.default_warehouse or args.warehouse
 
+	#Set the UOM to the Default Sales UOM or Default Purchase UOM if configured in the Item Master
+	if args.get('doctype') in ['Quotation', 'Sales Order', 'Delivery Note', 'Sales Invoice']:
+		uom = item.sales_uom if item.sales_uom else item.stock_uom
+	elif args.get('doctype') in ['Purchase Order', 'Purchase Receipt', 'Purchase Invoice']:
+		uom = item.purchase_uom if item.purchase_uom else item.stock_uom
+	else:
+		uom = item.stock_uom
+
+	args.uom = uom
+
 	out = frappe._dict({
 		"item_code": item.name,
 		"item_name": item.item_name,
@@ -178,7 +188,7 @@
 		"batch_no": None,
 		"item_tax_rate": json.dumps(dict(([d.tax_type, d.tax_rate] for d in
 			item.get("taxes")))),
-		"uom": item.stock_uom,
+		"uom": uom,
 		"min_order_qty": flt(item.min_order_qty) if args.doctype == "Material Request" else "",
 		"qty": args.qty or 1.0,
 		"stock_qty": args.qty or 1.0,