From 8f172fb2d6b98f84a9fc8ea5a3a031726a30eb79 Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Tue, 6 Sep 2022 20:04:12 +0200
Subject: [PATCH] REF: ensure to apply suffixes before concat step in merge
 code

---
 pandas/core/reshape/merge.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/core/reshape/merge.py b/pandas/core/reshape/merge.py
index 5052c27ea47f3..472984c65a897 100644
--- a/pandas/core/reshape/merge.py
+++ b/pandas/core/reshape/merge.py
@@ -764,8 +764,9 @@ def _reindex_and_concat(
 
         from pandas import concat
 
+        left.columns = llabels
+        right.columns = rlabels
         result = concat([left, right], axis=1, copy=copy)
-        result.columns = llabels.append(rlabels)
         return result
 
     def get_result(self, copy: bool = True) -> DataFrame: