From 2aedbdb76ff606febee27d235118bca28bd4a6ce Mon Sep 17 00:00:00 2001
From: Matias Chomicki <matias.chomicki@grafana.com>
Date: Mon, 12 Jan 2026 13:37:17 +0100
Subject: [PATCH] processing: support duplicated keys when parsing json logs
 (#116116)

* processing: support duplicated keys when parsing json logs

* Add regression test

* prettier
---
 .../logs/components/panel/processing.test.ts     | 16 ++++++++++++++++
 .../features/logs/components/panel/processing.ts |  4 +++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/public/app/features/logs/components/panel/processing.test.ts b/public/app/features/logs/components/panel/processing.test.ts
index 5998ff36d21..748c53b1df4 100644
--- a/public/app/features/logs/components/panel/processing.test.ts
+++ b/public/app/features/logs/components/panel/processing.test.ts
@@ -190,6 +190,22 @@ describe('preProcessLogs', () => {
       expect(logListModel.body).not.toBe(entry);
     });
 
+    test('Prettifies JSON with duplicate keys', () => {
+      const entry = '{"key": "value", "key": "otherValue"}';
+      const logListModel = createLogLine(
+        { entry },
+        {
+          escape: false,
+          order: LogsSortOrder.Descending,
+          timeZone: 'browser',
+          wrapLogMessage: true, // wrapped
+          prettifyJSON: true,
+        }
+      );
+      expect(logListModel.entry).toBe(entry);
+      expect(logListModel.body).not.toBe(entry);
+    });
+
     test('Prettifies and escapes wrapped JSON', () => {
       const entry = '{"key": "value", "otherKey": "other\\nValue"}';
       const logListModel = createLogLine(
diff --git a/public/app/features/logs/components/panel/processing.ts b/public/app/features/logs/components/panel/processing.ts
index 9132c2b7e6e..814481e87f2 100644
--- a/public/app/features/logs/components/panel/processing.ts
+++ b/public/app/features/logs/components/panel/processing.ts
@@ -135,7 +135,9 @@ export class LogListModel implements LogRowModel {
   get body(): string {
     if (this._body === undefined) {
       try {
-        const parsed = parse(this.raw);
+        const parsed = parse(this.raw, undefined, {
+          onDuplicateKey: ({ newValue }) => newValue,
+        });
         if (typeof parsed === 'object' && parsed !== null && !(parsed instanceof LosslessNumber)) {
           this._json = true;
         }