feat: Only update exploded items rate and amount

- Generate RM-Rate map from Items table (will include subassembly items with rate)
- Function to reset exploded item rate from above map
- `db_update` exploded item rate only if rate is changed
- Via Update Cost, only update exploded items rate, do not regenerate table again
- Exploded Items are regenerated on Save and Replace BOM job
- `calculate_exploded_cost` is run only via non doc events (Update Cost button, Update BOMs Cost Job)

erpnext/manufacturing/doctype/bom/bom.py

@@ -5,7 +5,7 @@ import functools
 import re
 from collections import deque
 from operator import itemgetter
-from typing import List
+from typing import Dict, List
 
 import frappe
 from frappe import _
@@ -185,6 +185,7 @@ class BOM(WebsiteGenerator):
 		self.validate_transfer_against()
 		self.set_routing_operations()
 		self.validate_operations()
+		self.update_exploded_items(save=False)
 		self.calculate_cost()
 		self.update_stock_qty()
 		self.update_cost(update_parent=False, from_child_bom=True, update_hour_rate=False, save=False)
@@ -391,8 +392,6 @@ class BOM(WebsiteGenerator):
 		if save:
 			self.db_update()
 
-		self.update_exploded_items(save=save)
-
 		# update parent BOMs
 		if self.total_cost != existing_bom_cost and update_parent:
 			parent_boms = frappe.db.sql_list(
@@ -594,6 +593,10 @@ class BOM(WebsiteGenerator):
 		self.calculate_op_cost(update_hour_rate)
 		self.calculate_rm_cost(save=save_updates)
 		self.calculate_sm_cost(save=save_updates)
+		if save_updates:
+			# not via doc event, table is not regenerated and needs updation
+			self.calculate_exploded_cost()
+
 		self.total_cost = self.operating_cost + self.raw_material_cost - self.scrap_material_cost
 		self.base_total_cost = (
 			self.base_operating_cost + self.base_raw_material_cost - self.base_scrap_material_cost
@@ -689,6 +692,36 @@ class BOM(WebsiteGenerator):
 		self.scrap_material_cost = total_sm_cost
 		self.base_scrap_material_cost = base_total_sm_cost
 
+	def calculate_exploded_cost(self):
+		"Set exploded row cost from it's parent BOM."
+		rm_rate_map = self.get_rm_rate_map()
+
+		for row in self.get("exploded_items"):
+			old_rate = flt(row.rate)
+			row.rate = rm_rate_map.get(row.item_code)
+			row.amount = flt(row.stock_qty) * row.rate
+
+			if old_rate != row.rate:
+				# Only db_update if unchanged
+				row.db_update()
+
+	def get_rm_rate_map(self) -> Dict[str, float]:
+		"Create Raw Material-Rate map for Exploded Items. Fetch rate from Items table or Subassembly BOM."
+		rm_rate_map = {}
+
+		for item in self.get("items"):
+			if item.bom_no:
+				# Get Item-Rate from Subassembly BOM
+				explosion_items = frappe.db.get_all(
+					"BOM Explosion Item", filters={"parent": item.bom_no}, fields=["item_code", "rate"]
+				)
+				explosion_item_rate = {item.item_code: flt(item.rate) for item in explosion_items}
+				rm_rate_map.update(explosion_item_rate)
+			else:
+				rm_rate_map[item.item_code] = flt(item.base_rate) / flt(item.conversion_factor or 1.0)
+
+		return rm_rate_map
+
 	def update_exploded_items(self, save=True):
 		"""Update Flat BOM, following will be correct data"""
 		self.get_exploded_items()

erpnext/manufacturing/doctype/bom_explosion_item/bom_explosion_item.json

@@ -169,13 +169,15 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2020-10-08 16:21:29.386212",
+ "modified": "2022-05-27 13:42:23.305455",
  "modified_by": "Administrator",
  "module": "Manufacturing",
  "name": "BOM Explosion Item",
+ "naming_rule": "Random",
  "owner": "Administrator",
  "permissions": [],
  "sort_field": "modified",
  "sort_order": "DESC",
+ "states": [],
  "track_changes": 1
 }

erpnext/manufacturing/doctype/bom_update_log/bom_updation_utils.py

@@ -120,7 +120,6 @@ def update_cost_in_boms(bom_list: List[str], docname: str) -> Dict[str, Dict]:
 	for bom in bom_list:
 		bom_doc = frappe.get_cached_doc("BOM", bom)
 		bom_doc.calculate_cost(save_updates=True, update_hour_rate=True)
-		# bom_doc.update_exploded_items(save=True) #TODO: edit exploded items rate
 		bom_doc.db_update()
 		updated_boms[bom] = True