From 164eeb84c0af028691b7691bd0f8c73ab662ef68 Mon Sep 17 00:00:00 2001
From: Weixie Cui <cuiweixie@gmail.com>
Date: Thu, 9 Jul 2026 12:15:00 +0800
Subject: [PATCH] internal/testlog: clone attrs before appending

WithAttrs and terminalFormat appended to h.attrs directly, which can
mutate the shared slice when it has spare capacity. Clone attrs first
to avoid corrupting parent handler state.
---
 internal/testlog/testlog.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/internal/testlog/testlog.go b/internal/testlog/testlog.go
index 8a3ea85438..8993d073c7 100644
--- a/internal/testlog/testlog.go
+++ b/internal/testlog/testlog.go
@@ -22,6 +22,7 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"slices"
 	"sync"
 
 	"github.com/ethereum/go-ethereum/log"
@@ -76,7 +77,7 @@ func (h *bufHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
 	copy(records[:], h.buf[:])
 	return &bufHandler{
 		buf:   records,
-		attrs: append(h.attrs, attrs...),
+		attrs: append(slices.Clone(h.attrs), attrs...),
 		level: h.level,
 	}
 }
@@ -186,7 +187,7 @@ func (h *bufHandler) terminalFormat(r slog.Record) string {
 		return true
 	})
 
-	attrs = append(h.attrs, attrs...)
+	attrs = append(slices.Clone(h.attrs), attrs...)
 
 	fmt.Fprintf(buf, "%s[%s] %s ", lvl, r.Time.Format(termTimeFormat), r.Message)
 	if length := len(r.Message); length < 40 {