fix: Require lnInst only for regular lns (openscd#1713)

Author: clepski

packages/plugins/src/editors/subscription/foundation.ts

@@ -690,7 +690,11 @@ export function canCreateValidExtRef(
     'lnInst',
     'doName',
   ].map(attr => fcda.getAttribute(attr));
-  if (!iedName || !ldInst || !lnClass || !lnInst || !doName) {
+
+  // lnInst is only required for ln that are not ln0
+  const hasValidLnInst = lnClass === 'LLN0' || !!lnInst;
+
+  if (!iedName || !ldInst || !lnClass || !hasValidLnInst || !doName) {
     return false;
   }
 

packages/plugins/test/testfiles/editors/bugfix1711-can-create-extref.scd

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<SCL xmlns="http://www.iec.ch/61850/2003/SCL" version="2007" revision="B" release="4" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ext="http://www.nrec.com">
+	<IED name="IED1" type="PCS-221S" originalSclVersion="2007" originalSclRevision="B">
+		<AccessPoint name="S1">
+			<Server>
+				<Authentication />
+				<LDevice inst="LD0">
+					<LN0 desc="LLN0" lnType="LLN0_type" lnClass="LLN0" inst="">
+						<DataSet name="ds1">
+							<FCDA ldInst="LD0" prefix="" lnClass="LLN0" doName="AnIn1"/>
+						</DataSet>
+						<GSEControl name="gseControl" datSet="ds1" confRev="10001" appID="gse1" />
+					</LN0>
+				</LDevice>
+			</Server>
+		</AccessPoint>
+	</IED>
+</SCL>

packages/plugins/test/unit/editors/subscription/foundation.test.ts

@@ -1,6 +1,7 @@
 import { expect } from '@open-wc/testing';
 
 import {
+  canCreateValidExtRef,
   createExtRefElement,
   getExistingSupervision,
   getExtRef,
@@ -334,4 +335,21 @@ describe('foundation', () => {
       expect(extRef).to.equal(expectedExtRef)
     });
   });
+
+  describe('regression test for bugfix 1711', () => {
+    beforeEach(async () => {
+      doc = await fetch('/test/testfiles/editors/bugfix1711-can-create-extref.scd')
+        .then(response => response.text())
+        .then(str => new DOMParser().parseFromString(str, 'application/xml'));
+    });
+
+    it('should return true for canCreateValidExtRef on FCDA without lnInst for LN0', () => {
+      const fcda = doc.querySelector('FCDA')!;
+      const controlBlock = doc.querySelector('IED[name="IED1"] GSEControl[name="gseControl"]')!;
+
+      const canCreateExtRef = canCreateValidExtRef(fcda, controlBlock);
+
+      expect(canCreateExtRef).to.be.true;
+    });
+  });
 });