From 0723a51e87dea4d41af7359f5bd430f2a5524afc Mon Sep 17 00:00:00 2001
From: ismail simsek <ismailsimsek09@gmail.com>
Date: Thu, 24 Jul 2025 20:12:43 +0200
Subject: [PATCH] Prometheus: Fix adding labels to the query with empty values
 (#108611)

* values can be empty

* remove a test
---
 .../grafana-prometheus/src/add_label_to_query.ts     |  2 +-
 .../grafana-prometheus/src/language_utils.test.ts    | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/packages/grafana-prometheus/src/add_label_to_query.ts b/packages/grafana-prometheus/src/add_label_to_query.ts
index 7c75e6e14ec..06e82fcbf00 100644
--- a/packages/grafana-prometheus/src/add_label_to_query.ts
+++ b/packages/grafana-prometheus/src/add_label_to_query.ts
@@ -21,7 +21,7 @@ import { PromVisualQuery } from './querybuilder/types';
  * @param operator
  */
 export function addLabelToQuery(query: string, key: string, value: string | number, operator = '='): string {
-  if (!key || !value) {
+  if (!key) {
     throw new Error('Need label to add to query.');
   }
 
diff --git a/packages/grafana-prometheus/src/language_utils.test.ts b/packages/grafana-prometheus/src/language_utils.test.ts
index 5ba14363da7..555634f898e 100644
--- a/packages/grafana-prometheus/src/language_utils.test.ts
+++ b/packages/grafana-prometheus/src/language_utils.test.ts
@@ -191,6 +191,18 @@ describe('expandRecordingRules()', () => {
     const result = expandRecordingRules(query, mapping);
     expect(result).toBe(expected);
   });
+
+  it('when there is an empty label value it should still be able to expand the rule', () => {
+    const query = `sum(max by (cluster, container) (pod_cpu:active:kube_limits{container!="", cluster=~"pink"}))`;
+    const mapping = {
+      'pod_cpu:active:kube_limits': {
+        expandedQuery: `kube_limits{job!="", resource="cpu"} * on (namespace, pod, cluster) group_left () max by (namespace, pod, cluster) ((kube_pod_status_phase{phase=~"Pending|Running"} == 1))`,
+      },
+    };
+    const expected = `sum(max by (cluster, container) (kube_limits{job!="", resource="cpu", container!="", cluster=~"pink"} * on (namespace, pod, cluster) group_left () max by (namespace, pod, cluster) ((kube_pod_status_phase{phase=~"Pending|Running", container!="", cluster=~"pink"} == 1))))`;
+    const result = expandRecordingRules(query, mapping);
+    expect(result).toBe(expected);
+  });
 });
 
 describe('escapeLabelValueInExactSelector()', () => {