From ac4f076765773d8b4aa44c89acb9eca034ad55a0 Mon Sep 17 00:00:00 2001
From: seiya <20365512+seiyab@users.noreply.github.com>
Date: Fri, 2 Oct 2026 00:08:40 +0000
Subject: [PATCH 1/2] test(writer): reproduce trailing bytes on overwrite

Co-Authored-By: codex <codex@openai.com>
---
 pkg/writer/writer_test.go | 43 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 pkg/writer/writer_test.go

diff --git a/pkg/writer/writer_test.go b/pkg/writer/writer_test.go
new file mode 100644
index 000000000..58e05735f
--- /dev/null
+++ b/pkg/writer/writer_test.go
@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package writer
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestWriteFileTruncatesExistingFile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "file.txt")
+	if err := os.WriteFile(path, []byte("123456"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := WriteFile(path, "abc"); err != nil {
+		t.Fatal(err)
+	}
+	content, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(content) != "abc" {
+		t.Fatalf("got %q, want %q", content, "abc")
+	}
+}

From f1ccf4679f1ff4246714cec4e175766562ecc947 Mon Sep 17 00:00:00 2001
From: seiya <20365512+seiyab@users.noreply.github.com>
Date: Fri, 2 Oct 2026 00:08:56 +0000
Subject: [PATCH 2/2] fix(writer): truncate existing files when writing

Co-Authored-By: codex <codex@openai.com>
---
 pkg/writer/writer.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/writer/writer.go b/pkg/writer/writer.go
index ff08d2592..d587fcbd1 100644
--- a/pkg/writer/writer.go
+++ b/pkg/writer/writer.go
@@ -32,7 +32,7 @@ func ReplaceFile(filePath, content string) error {
 
 // WriteFile write file to path
 func WriteFile(filePath, content string) error {
-	file, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE, 0o666)
+	file, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o666)
 	if err != nil {
 		return err
 	}