Read an intermediate delivery notification as a report, and keep it out of the merge

test/dlr.test.ts

@@ -145,6 +145,7 @@ describe('dlrFromPdu()', () => {
 		assert.equal(dlr.smsId, undefined);
 		assert.equal(dlr.statusMsg, 'UNKNOWN');
 		assert.equal(dlr.statusId, 7);
+		assert.equal(dlr.intermediate, false);
 	});
 
 	// pduToObj leaves a UDH-carrying short_message a buffer, so the body needs decoding before it
@@ -196,17 +197,31 @@ describe('dlrFromPdu()', () => {
 		assert.equal(dlr.statusMsg, 'DELIVERED');
 	});
 
-	test('leaves a message the peer marked as another type to arrive as an SMS', () => {
+	test('leaves a message the far-end SME marked as another type to arrive as an SMS', () => {
 		for (const esmClass of [
 			consts.ESM_CLASS.CONVERSATION_ABORT,
 			consts.ESM_CLASS.DELIVERY_ACKNOWLEDGEMENT,
-			consts.ESM_CLASS.INTERMEDIATE_DELIVERY,
 			consts.ESM_CLASS.USER_ACKNOWLEDGEMENT,
 		]) {
 			assert.equal(dlrFromPdu(deliverSm(receiptText, undefined, esmClass)), undefined);
 		}
 	});
 
+	test('reads an intermediate delivery notification as a report, marked as one', () => {
+		const enroute = 'id:0195f0c7 sub:001 dlvrd:000 submit date:2508251430 done date:2508251431 stat:ENROUTE err:000 text:';
+		const dlr = dlrFromPdu(deliverSm(enroute, undefined, consts.ESM_CLASS.INTERMEDIATE_DELIVERY));
+
+		assert.ok(dlr);
+		assert.equal(dlr.smsId, '0195f0c7');
+		assert.equal(dlr.statusMsg, 'ENROUTE');
+		assert.equal(dlr.intermediate, true);
+
+		const unreadable = dlrFromPdu(deliverSm('no fields here', undefined, consts.ESM_CLASS.INTERMEDIATE_DELIVERY));
+
+		assert.ok(unreadable, 'the marker makes it a report whatever the body parses to');
+		assert.equal(unreadable.intermediate, true);
+	});
+
 	test('exposes the raw receipt alongside the resolved fields', () => {
 		const dlr = dlrFromPdu(deliverSm(receiptText));
 

test/session-extras.test.ts

@@ -203,10 +203,11 @@ describe('merged delivery reports', () => {
 });
 
 describe('merging segment statuses', () => {
-	function receipt(smsId: string, statusMsg: MessageState): Dlr {
+	function receipt(smsId: string, statusMsg: MessageState, intermediate = false): Dlr {
 		return {
 			doneDate: undefined,
 			errorCode: undefined,
+			intermediate,
 			receipt: undefined,
 			smsId,
 			statusId: consts.MESSAGE_STATE[statusMsg],
@@ -214,6 +215,24 @@ describe('merging segment statuses', () => {
 		};
 	}
 
+	// Filling every slot with a non-final report merges early and spends the base, so the receipts
+	// that say what actually happened would report nothing.
+	test('never counts an intermediate report toward a merge', () => {
+		const merger = new DlrMerger({ log: silentLog, max: 10, now: () => 0, timeout: 60_000 });
+
+		merger.expect(['msg-1', 'msg-2']);
+
+		assert.equal(merger.collect(receipt('msg-1', 'ENROUTE', true)), undefined);
+		assert.equal(merger.collect(receipt('msg-2', 'ENROUTE', true)), undefined);
+		assert.equal(merger.collect(receipt('msg-1', 'DELIVERED')), undefined);
+
+		const merged = merger.collect(receipt('msg-2', 'DELIVERED'));
+
+		assert.ok(merged);
+		assert.equal(merged.statusMsg, 'DELIVERED');
+		assert.equal(merged.segments.length, 2);
+	});
+
 	// MESSAGE_STATE is a flat enum: ACCEPTED is 6 where UNDELIVERABLE is 5, so reducing on the
 	// wire value called a part-failed message delivered.
 	test('reports the worse of two states the wire numbers the other way round', () => {

test/session.test.ts

@@ -685,7 +685,7 @@ describe('receiving', () => {
 		assert.equal(answered.pduObj.params.message_id, 'inbound-id');
 	});
 
-	test('hands a client a receipt it cannot read as a dlr rather than as an sms', async t => {
+	test('hands a client a report as a dlr rather than as an sms', async t => {
 		const { peer, session } = await inbound(t);
 		const reported = once<Dlr>(resolve => { session.on('dlr', resolve); });
 		let messages = 0;
@@ -711,6 +711,28 @@ describe('receiving', () => {
 
 		assert.ok(answered.pduObj);
 		assert.equal(answered.pduObj.cmdName, 'deliver_sm_resp');
+
+		const notified = once<Dlr>(resolve => { session.on('dlr', resolve); });
+		const notification = peer.send({
+			cmdName: 'deliver_sm',
+			params: {
+				destination_addr: '46709771337',
+				esm_class: consts.ESM_CLASS.INTERMEDIATE_DELIVERY,
+				short_message: 'id:0195f0c7 stat:ENROUTE err:000 text:',
+				source_addr: '46701113311',
+			},
+		});
+		const report = await raceWithin(2000, notified);
+
+		assert.ok(report, 'an intermediate notification is the MC reporting on our send, not an inbound SMS');
+		assert.equal(report.intermediate, true);
+		assert.equal(report.statusMsg, 'ENROUTE');
+		assert.equal(messages, 0);
+
+		const answeredNotification = await notification;
+
+		assert.ok(answeredNotification.pduObj);
+		assert.equal(answeredNotification.pduObj.cmdName, 'deliver_sm_resp');
 	});
 
 	test('reassembles a multipart inbound SMS before the sms event', async t => {
@@ -1494,6 +1516,7 @@ describe('merged delivery report bounds', () => {
 		return {
 			doneDate: undefined,
 			errorCode: undefined,
+			intermediate: false,
 			receipt: undefined,
 			smsId,
 			statusId: 2,