From 6c566a391d97b7f5b41c37eb4313fff629706ac7 Mon Sep 17 00:00:00 2001
From: Sven Grossmann <sven.grossmann@grafana.com>
Date: Wed, 18 Jan 2023 10:14:42 +0100
Subject: [PATCH] Loki: Use queries `maxLines` if configured, even if it is
 zero (#61652)

* user `query.maxLines` even if it is zero

* remove unnecessary comment
---
 public/app/plugins/datasource/loki/datasource.test.ts | 4 ++++
 public/app/plugins/datasource/loki/datasource.ts      | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/public/app/plugins/datasource/loki/datasource.test.ts b/public/app/plugins/datasource/loki/datasource.test.ts
index eff45c8ea56..f2333e8c6bd 100644
--- a/public/app/plugins/datasource/loki/datasource.test.ts
+++ b/public/app/plugins/datasource/loki/datasource.test.ts
@@ -176,6 +176,10 @@ describe('LokiDatasource', () => {
       await runTest(80, '40', 80, undefined);
     });
 
+    it('should use query max lines, if both exist, even if it is 0', async () => {
+      await runTest(0, '40', 0, undefined);
+    });
+
     it('should report query interaction', async () => {
       await runTest(80, '40', 80, CoreApp.Explore);
       expect(reportInteraction).toHaveBeenCalledWith(
diff --git a/public/app/plugins/datasource/loki/datasource.ts b/public/app/plugins/datasource/loki/datasource.ts
index b403051b693..a5195b5f920 100644
--- a/public/app/plugins/datasource/loki/datasource.ts
+++ b/public/app/plugins/datasource/loki/datasource.ts
@@ -174,7 +174,7 @@ export class LokiDatasource
   query(request: DataQueryRequest<LokiQuery>): Observable<DataQueryResponse> {
     const queries = request.targets
       .map(getNormalizedLokiQuery) // "fix" the `.queryType` prop
-      .map((q) => ({ ...q, maxLines: q.maxLines || this.maxLines })); // set maxLines if not set
+      .map((q) => ({ ...q, maxLines: q.maxLines ?? this.maxLines }));
 
     const fixedRequest: DataQueryRequest<LokiQuery> & { targets: LokiQuery[] } = {
       ...request,