Merge pull request #7157 from rohitwaghchaure/timesheet_po_issue

[fix] Timesheet datetime issue
diff --git a/erpnext/projects/doctype/timesheet/timesheet.py b/erpnext/projects/doctype/timesheet/timesheet.py
index 5483320..f853692 100644
--- a/erpnext/projects/doctype/timesheet/timesheet.py
+++ b/erpnext/projects/doctype/timesheet/timesheet.py
@@ -79,7 +79,7 @@
 			self.status = "Completed"
 
 	def set_dates(self):
-		if self.docstatus < 2:
+		if self.docstatus < 2 and self.time_logs:
 			start_date = min([d.from_time for d in self.time_logs])
 			end_date = max([d.to_time for d in self.time_logs])