fix: employee user creation

- consider prefered email as default in employee creation

- remove unused user parameter from `create_user` API

- remove unnecessary validations on user ID, already checked by user doctype hooks

- set company email only if empty

(cherry picked from commit 613d36a139)

erpnext/setup/doctype/employee/employee.js

@@ -56,7 +56,8 @@ frappe.ui.form.on("Employee", {
 							fieldname: "email",
 							label: __("Email"),
 							reqd: 1,
-							default: frm.doc.company_email || frm.doc.personal_email || frm.doc.user_id,
+							default:
+								frm.doc.prefered_email || frm.doc.company_email || frm.doc.personal_email,
 						},
 						{
 							fieldtype: "Check",

erpnext/setup/doctype/employee/employee.py

@@ -416,31 +416,19 @@ def deactivate_sales_person(status=None, employee=None):
 
 
 @frappe.whitelist()
-def create_user(
-	employee: str, user: str | None = None, email: str | None = None, create_user_permission: int = 0
-) -> str:
-	if not employee:
-		frappe.throw(_("Employee is required"))
-
+def create_user(employee: str, email: str | None = None, create_user_permission: int = 0) -> str:
 	emp = frappe.get_doc("Employee", employee)
-
-	if email:
-		email = cstr(email).strip().lower()
-	else:
-		email = emp.company_email
-
-	if not email:
-		frappe.throw(_("Email is required to create a user"))
-
-	validate_email_address(email, True)
-
 	if emp.user_id:
 		frappe.throw(_("Employee {0} already has a linked user").format(emp.name))
 
-	if frappe.db.exists("User", email):
-		frappe.throw(_("User {0} already exists").format(email))
+	if not email:
+		email = emp.company_email
+	if not email:
+		frappe.throw(_("Email is required to create a user"))
 
+	email = validate_email_address(email, True)
 	employee_name = emp.employee_name.split(" ")
+	first_name = employee_name[0]
 	middle_name = last_name = ""
 
 	if len(employee_name) >= 3:
@@ -449,12 +437,9 @@ def create_user(
 	elif len(employee_name) == 2:
 		last_name = employee_name[1]
 
-	first_name = employee_name[0]
-
 	user = frappe.new_doc("User")
 	user.update(
 		{
-			"name": email,
 			"email": email,
 			"enabled": 1,
 			"first_name": first_name,
@@ -471,7 +456,9 @@ def create_user(
 	user.insert()
 
 	emp.reload()
-	emp.company_email = email
+	emp.user_id = user.name
+	if not emp.company_email:
+		emp.company_email = email
 	if not emp.prefered_contact_email:
 		emp.prefered_contact_email = "Company Email"
 	emp.save()