From d49deebefe6e1fc45330fdb6cfe67edde22188c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zolt=C3=A1n=20Bedi?= <zoltan.bedi@gmail.com>
Date: Fri, 14 May 2021 15:57:40 +0200
Subject: [PATCH] Prometheus: fix toggling exemplars in range mode (#34099)

---
 public/app/plugins/datasource/prometheus/datasource.test.ts | 4 ++++
 public/app/plugins/datasource/prometheus/datasource.ts      | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/public/app/plugins/datasource/prometheus/datasource.test.ts b/public/app/plugins/datasource/prometheus/datasource.test.ts
index e24f1d49b1a..d4878c5ce87 100644
--- a/public/app/plugins/datasource/prometheus/datasource.test.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.test.ts
@@ -1746,6 +1746,7 @@ describe('prepareTargets', () => {
       const target: PromQuery = {
         refId: 'A',
         expr: 'up',
+        requestId: '2A',
       };
 
       const { queries, activeTargets, panelId, end, start } = getPrepareTargetsContext(target);
@@ -1804,6 +1805,7 @@ describe('prepareTargets', () => {
           expr: 'up',
           range: true,
           instant: true,
+          requestId: '2A',
         };
 
         const { queries, activeTargets, panelId, end, start } = getPrepareTargetsContext(target, CoreApp.Explore);
@@ -1861,6 +1863,7 @@ describe('prepareTargets', () => {
           expr: 'up',
           instant: true,
           range: false,
+          requestId: '2A',
         };
 
         const { queries, activeTargets, panelId, end, start } = getPrepareTargetsContext(target, CoreApp.Explore);
@@ -1893,6 +1896,7 @@ describe('prepareTargets', () => {
         expr: 'up',
         range: true,
         instant: false,
+        requestId: '2A',
       };
 
       const { queries, activeTargets, panelId, end, start } = getPrepareTargetsContext(target, CoreApp.Explore);
diff --git a/public/app/plugins/datasource/prometheus/datasource.ts b/public/app/plugins/datasource/prometheus/datasource.ts
index 1a6625e875a..bfcbcec3fb5 100644
--- a/public/app/plugins/datasource/prometheus/datasource.ts
+++ b/public/app/plugins/datasource/prometheus/datasource.ts
@@ -198,8 +198,9 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
   prepareTargets = (options: DataQueryRequest<PromQuery>, start: number, end: number) => {
     const queries: PromQueryRequest[] = [];
     const activeTargets: PromQuery[] = [];
+    const clonedTargets = cloneDeep(options.targets);
 
-    for (const target of options.targets) {
+    for (const target of clonedTargets) {
       if (!target.expr || target.hide) {
         continue;
       }