[fix] Show debit note button in purchase invoice
diff --git a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
index 358cf39..50a50d9 100644
--- a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
+++ b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.js
@@ -28,7 +28,7 @@
 					this.frm.add_custom_button(__('Payment'), this.make_bank_entry, __("Make"));
 					cur_frm.page.set_inner_btn_group_as_primary(__("Make"));
 				}
-				if(Math.abs(flt(doc.outstanding_amount)) < flt(doc.grand_total)) {
+				if(doc.outstanding_amount >= 0 || Math.abs(flt(doc.outstanding_amount)) < flt(doc.grand_total)) {
 					cur_frm.add_custom_button(__('Debit Note'), this.make_debit_note, __("Make"));
 				}
 			}