harden replicated get_analytics peer-response unwrap

Guarantee the unwrapped peer response is always an array so a malformed
peer (e.g. a non-array `results`) is treated as empty rather than throwing
during the merge, preserving the best-effort guarantee.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kriszyp

resources/analytics/read.ts

@@ -116,8 +116,11 @@ async function* mergeAnalyticsFromPeers(
 		.filter((node) => node.name !== thisNode)
 		.map((node) =>
 			sendOperationToNode(node, peerReq).then(
-				// an array response is wrapped as `{ results }` over the replication channel
-				(response): Metric[] => (Array.isArray(response) ? response : (response?.results ?? [])),
+				// an array response is wrapped as `{ results }` over the replication channel;
+				// fall back to an empty list for any other (malformed) shape so a bad peer
+				// can't break the merge
+				(response): Metric[] =>
+					Array.isArray(response) ? response : Array.isArray(response?.results) ? response.results : [],
 				(error: Error): Metric[] => {
 					logger.warn(`get_analytics replication to node '${node.name}' failed; omitting its results`, error);
 					return [];

unitTests/resources/analytics/read.test.js

@@ -419,6 +419,18 @@ describe('getOp (replicated fan-out)', () => {
 		expect(result).to.deep.equal([{ id: 5, metric: 'm', node: 'peer-a' }]);
 	});
 
+	it('treats a malformed peer response (non-array results) as empty', async () => {
+		global.server.nodes = [{ name: 'peer-good' }, { name: 'peer-weird' }];
+		sendOperationStub
+			.withArgs(sinon.match({ name: 'peer-good' }))
+			.resolves({ results: [{ id: 1, metric: 'm', node: 'peer-good' }] });
+		sendOperationStub.withArgs(sinon.match({ name: 'peer-weird' })).resolves({ results: 'not-an-array' });
+
+		const result = await collect(await getOp({ metric: 'm', replicated: true }));
+
+		expect(result).to.deep.equal([{ id: 1, metric: 'm', node: 'peer-good' }]);
+	});
+
 	it('includes local node results ahead of peer results', async () => {
 		sinon
 			.stub(hostnames, 'getAnalyticsHostnameTable')