Currency validation in gl entry

erpnext/accounts/doctype/account/account.py

@@ -28,6 +28,7 @@ class Account(Document):
 		self.validate_warehouse_account()
 		self.validate_frozen_accounts_modifier()
 		self.validate_balance_must_be_debit_or_credit()
+		self.validate_account_currency()
 
 	def validate_parent(self):
 		"""Fetch Parent Details and validate parent account"""
@@ -86,6 +87,14 @@ class Account(Document):
 				frappe.throw(_("Account balance already in Debit, you are not allowed to set 'Balance Must Be' as 'Credit'"))
 			elif account_balance < 0 and self.balance_must_be == "Debit":
 				frappe.throw(_("Account balance already in Credit, you are not allowed to set 'Balance Must Be' as 'Debit'"))
+				
+	def validate_account_currency(self):
+		if not self.currency:
+			self.currency = frappe.db.get_value("Company", self.company, "default_currency")
+			
+		elif self.currency != frappe.db.get_value("Account", self.name, "currency"):
+			if frappe.db.get_value("GL Entry", {"account": self.name}):
+				frappe.throw(_("Currency can not be changed after making entries using some other currency"))
 
 	def convert_group_to_ledger(self):
 		if self.check_if_child_exists():

erpnext/accounts/doctype/gl_entry/gl_entry.py

@@ -20,6 +20,7 @@ class GLEntry(Document):
 		self.check_pl_account()
 		self.validate_cost_center()
 		self.validate_party()
+		self.validate_currency()
 
 	def on_update_with_args(self, adv_adj, update_outstanding = 'Yes'):
 		self.validate_account_details(adv_adj)
@@ -98,6 +99,31 @@ class GLEntry(Document):
 			if not frozen_accounts_modifier in frappe.get_roles():
 				if frappe.db.get_value(self.party_type, self.party, "is_frozen"):
 					frappe.throw("{0} {1} is frozen".format(self.party_type, self.party), CustomerFrozen)
+					
+	def validate_currency(self):
+		company_currency = frappe.db.get_value("Company", self.company, "default_currency")
+		account_currency = frappe.db.get_value("Account", self.account, "currency") or company_currency
+
+		if not self.currency:
+			self.currency = company_currency
+
+		if account_currency != self.currency:
+			frappe.throw(_("Accounting Entry for {0} can only be made in currency: {1}")
+				.format(self.account, (account_currency or company_currency)))
+				
+		if self.party_type and self.party:
+			existing_gle = frappe.db.get_value("GL Entry", 
+				{"party_type": self.party_type, "party": self.party}, ["name", "currency"])
+			if not existing_gle:
+				party_currency = frappe.db.get_value(self.party_type, self.party, "currency") or company_currency
+				if party_currency != account_currency:
+					frappe.throw(_("Invalid Account {0}. Account Currency must be {1}, same as {2}: {3}")
+						.format(self.account, party_currency, self.party_type, self.party))
+			else:
+				currency_in_existing_entries = existing_gle.currency or company_currency
+				if currency_in_existing_entries != self.currency:
+					frappe.throw(_("Accounting Entry for {0}: {1} can only be made in currency: {2}")
+						.format(self.party_type, self.party, currency_in_existing_entries))
 
 def validate_balance_type(account, adv_adj=False):
 	if not adv_adj and account:

erpnext/accounts/party.py

@@ -7,7 +7,7 @@ import frappe
 import datetime
 from frappe import _, msgprint, scrub
 from frappe.defaults import get_user_permissions
-from frappe.utils import add_days, getdate, formatdate, flt, get_first_day, date_diff, nowdate
+from frappe.utils import add_days, getdate, formatdate, get_first_day, date_diff
 from erpnext.utilities.doctype.address.address import get_address_display
 from erpnext.utilities.doctype.contact.contact import get_contact_details
 
@@ -141,7 +141,16 @@ def set_account_and_due_date(party, account, party_type, company, posting_date,
 		"due_date": get_due_date(posting_date, party_type, party, company)
 	}
 	return out
-
+	
+def validate_party_account(party):
+	party_account_defined_for_companies = [d.company for d in party.get("party_accounts")]
+	
+	for company, company_currency in frappe.db.sql("select name, default_currency from `tabCompany`"):
+		if party.currency and party.currency != company_currency \
+			and company not in party_account_defined_for_companies:
+			frappe.throw(_("Please mention Party Account for company {0}, as party currency is different than company's default currency")
+				.format(company))
+				
 @frappe.whitelist()
 def get_party_account(company, party, party_type):
 	"""Returns the account for the given `party`.

erpnext/buying/doctype/supplier/supplier.py

@@ -8,6 +8,7 @@ from frappe import msgprint, _
 from frappe.model.naming import make_autoname
 from erpnext.utilities.address_and_contact import load_address_and_contact
 from erpnext.utilities.transaction_base import TransactionBase
+from erpnext.accounts.party import validate_party_account
 
 class Supplier(TransactionBase):
 	def get_feed(self):
@@ -44,6 +45,8 @@ class Supplier(TransactionBase):
 		if frappe.defaults.get_global_default('supp_master_name') == 'Naming Series':
 			if not self.naming_series:
 				msgprint(_("Series is mandatory"), raise_exception=1)
+				
+		validate_party_account(self)
 
 	def get_contacts(self,nm):
 		if nm:

erpnext/selling/doctype/customer/customer.py

@@ -10,6 +10,7 @@ from frappe.utils import flt
 
 from erpnext.utilities.transaction_base import TransactionBase
 from erpnext.utilities.address_and_contact import load_address_and_contact
+from erpnext.accounts.party import validate_party_account
 
 class Customer(TransactionBase):
 	def get_feed(self):
@@ -26,12 +27,13 @@ class Customer(TransactionBase):
 		else:
 			self.name = make_autoname(self.naming_series+'.#####')
 
-	def validate_values(self):
+	def validate_mandatory(self):
 		if frappe.defaults.get_global_default('cust_master_name') == 'Naming Series' and not self.naming_series:
 			frappe.throw(_("Series is mandatory"), frappe.MandatoryError)
-
+			
 	def validate(self):
-		self.validate_values()
+		self.validate_mandatory()
+		validate_party_account(self)
 
 	def update_lead_status(self):
 		if self.lead_name: