From 6059ef3d83a235ed47f5d81e5663e662e7c9b340 Mon Sep 17 00:00:00 2001
From: Ihor Yeromin <yeryomin.igor@gmail.com>
Date: Fri, 10 Oct 2025 14:51:45 +0200
Subject: [PATCH] Fix: Sorting with sparse arrays containing empty values
 (#112114)

---
 .../src/dataframe/processDataFrame.test.ts       | 12 ++++++++++++
 .../src/dataframe/processDataFrame.ts            | 16 +++++++++-------
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/packages/grafana-data/src/dataframe/processDataFrame.test.ts b/packages/grafana-data/src/dataframe/processDataFrame.test.ts
index 72b3041d87c..5c7593e91c0 100644
--- a/packages/grafana-data/src/dataframe/processDataFrame.test.ts
+++ b/packages/grafana-data/src/dataframe/processDataFrame.test.ts
@@ -365,6 +365,7 @@ describe('sorted DataFrame', () => {
       { name: 'fourth', type: FieldType.time, values: [1, 2, 3], nanos: [10, 20, 30] },
     ],
   });
+
   it('Should sort numbers', () => {
     const sorted = sortDataFrame(frame, 0, true);
     expect(sorted.length).toEqual(3);
@@ -386,6 +387,17 @@ describe('sorted DataFrame', () => {
     expect(sorted.fields[3].values).toEqual([3, 2, 1]);
     expect(sorted.fields[3].nanos).toEqual([30, 20, 10]);
   });
+
+  it('Should handle arrays with empty values correctly', () => {
+    // Create a sparse array with empty slots (undefined values)
+    const values = ['502', '502', , '500', '500', '200', '404']; // Note the empty slot at index 2
+    const frame = toDataFrame({
+      fields: [{ name: 'status', type: FieldType.string, values }],
+    });
+    const sorted = sortDataFrame(frame, 0, false);
+
+    expect(sorted.fields[0].values).toEqual(['200', '404', '500', '500', '502', '502', undefined]);
+  });
 });
 
 describe('sorted DataFrame by nanos', () => {
diff --git a/packages/grafana-data/src/dataframe/processDataFrame.ts b/packages/grafana-data/src/dataframe/processDataFrame.ts
index 4a028b6b4fd..14621547725 100644
--- a/packages/grafana-data/src/dataframe/processDataFrame.ts
+++ b/packages/grafana-data/src/dataframe/processDataFrame.ts
@@ -429,18 +429,20 @@ export function sortDataFrame(data: DataFrame, sortIndex?: number, reverse = fal
 
   return {
     ...data,
-    fields: data.fields.map((f) => {
-      const newF = {
-        ...f,
-        values: f.values.map((v, i) => f.values[index[i]]),
+    fields: data.fields.map((field) => {
+      const newValues = Array.from({ length: field.values.length }, (_, i) => field.values[index[i]]);
+
+      const newField = {
+        ...field,
+        values: newValues,
       };
 
       // only add .nanos if it exists
-      const { nanos } = f;
+      const { nanos } = field;
       if (nanos !== undefined) {
-        newF.nanos = nanos.map((n, i) => nanos[index[i]]);
+        newField.nanos = Array.from({ length: nanos.length }, (_, i) => nanos[index[i]]);
       }
-      return newF;
+      return newField;
     }),
   };
 }