# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 2022-03-25 05:05:36
# Node ID db93041e5b1ca454167af6adcea4520da21e80e0
# Parent  0f0e3830c099b1293e023bcaa05da838744ee186

filemerge: use new function for getting first line of string

Differential Revision: https://phab.mercurial-scm.org/D12411

diff --git a/mercurial/filemerge.py b/mercurial/filemerge.py
--- a/mercurial/filemerge.py
+++ b/mercurial/filemerge.py
@@ -848,7 +848,7 @@ def _populate_label_detail(input, templa
 
     props = {b'ctx': ctx}
     templateresult = template.renderdefault(props)
-    input.label_detail = templateresult.splitlines()[0]  # split for safety
+    input.label_detail = stringutil.firstline(templateresult)  # avoid '\n'
 
 
 def _populate_label_details(repo, inputs, tool=None):