From 51aa5c99d5eff4f897faafccb6a176640083198d Mon Sep 17 00:00:00 2001
From: yp05327 <576951401@qq.com>
Date: Thu, 16 May 2024 00:02:57 +0000
Subject: [PATCH] fix

---
 web_src/js/features/repo-issue.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/web_src/js/features/repo-issue.js b/web_src/js/features/repo-issue.js
index 8ee681aedc5f9..a28416c300dc0 100644
--- a/web_src/js/features/repo-issue.js
+++ b/web_src/js/features/repo-issue.js
@@ -638,8 +638,9 @@ export function initRepoIssueTitleEdit() {
         }
       }
       if (prTargetUpdateUrl) {
-        const newTargetBranch = document.querySelector('#pull-target-branch').getAttribute('data-branch');
-        const oldTargetBranch = document.querySelector('#branch_target').textContent;
+        // merged pr can not edit target branch, so they maybe null
+        const newTargetBranch = document.querySelector('#pull-target-branch')?.getAttribute('data-branch');
+        const oldTargetBranch = document.querySelector('#branch_target')?.textContent;
         if (newTargetBranch !== oldTargetBranch) {
           const resp = await POST(prTargetUpdateUrl, {data: new URLSearchParams({target_branch: newTargetBranch})});
           if (!resp.ok) {