[IMP] account: Trigger a validation error when trying to set the same currency on a journal as on its parent company.

Until v12, doing this is wrong. The currency_id field of account.journal should only be used if the journal is in a different currency. Otherwise, this field should stay empty.

//NOTE FOR FORWARD-PORT: this commit should not be ported to 12.0 and further.

addons/account/i18n/account.pot

@@ -10051,3 +10051,8 @@ msgstr ""
 msgid "→ Count"
 msgstr ""
 
+#. module: account
+#: code:addons/account/models/account.py:309
+#, python-format
+msgid "Currency field should only be set if the journal's currency is different from the company's. Leave the field blank to use company currency."
+msgstr ""

addons/account/models/account.py

@@ -305,6 +305,8 @@ class AccountJournal(models.Model):
     @api.constrains('currency_id', 'default_credit_account_id', 'default_debit_account_id')
     def _check_currency(self):
         if self.currency_id:
+            if self.currency_id == self.company_id.currency_id:
+                raise ValidationError(_("Currency field should only be set if the journal's currency is different from the company's. Leave the field blank to use company currency."))
             if self.default_credit_account_id and not self.default_credit_account_id.currency_id.id == self.currency_id.id:
                 raise ValidationError(_('Configuration error!\nThe currency of the journal should be the same than the default credit account.'))
             if self.default_debit_account_id and not self.default_debit_account_id.currency_id.id == self.currency_id.id: