From 61dbb5b7cea1b8d00ada896fbe3ee18f3906f468 Mon Sep 17 00:00:00 2001
From: kmg0308 <113580700+kmg0308@users.noreply.github.com>
Date: Mon, 29 Jun 2026 19:40:36 +0900
Subject: [PATCH] Truncate export files when rewriting

---
 src/export/mod.rs   |  5 +++--
 src/export/tests.rs | 14 +++++++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/export/mod.rs b/src/export/mod.rs
index 3947a2e50..9132b8e31 100644
--- a/src/export/mod.rs
+++ b/src/export/mod.rs
@@ -1,4 +1,4 @@
-use std::fs::{File, OpenOptions};
+use std::fs::File;
 use std::io::Write;
 
 mod asciidoc;
@@ -156,7 +156,8 @@ impl ExportManager {
 
 /// Write the given content to a file with the specified name
 fn write_to_file(filename: &str, content: &[u8]) -> Result<()> {
-    let mut file = OpenOptions::new().write(true).open(filename)?;
+    let mut file = File::create(filename)
+        .with_context(|| format!("Could not create export file '{filename}'"))?;
     file.write_all(content)
         .with_context(|| format!("Failed to export results to '{filename}'"))
 }
diff --git a/src/export/tests.rs b/src/export/tests.rs
index bd7ea7963..f249ca7c4 100644
--- a/src/export/tests.rs
+++ b/src/export/tests.rs
@@ -1,4 +1,4 @@
-use super::Exporter;
+use super::{write_to_file, Exporter};
 use crate::benchmark::benchmark_result::BenchmarkResult;
 use crate::export::asciidoc::AsciidocExporter;
 use crate::export::orgmode::OrgmodeExporter;
@@ -6,6 +6,18 @@ use crate::util::units::Unit;
 use crate::{export::markdown::MarkdownExporter, options::SortOrder};
 use std::collections::BTreeMap;
 
+#[test]
+fn write_to_file_truncates_existing_content() {
+    let tempdir = tempfile::tempdir().unwrap();
+    let path = tempdir.path().join("results.md");
+    let filename = path.to_str().unwrap();
+
+    write_to_file(filename, b"long benchmark export").unwrap();
+    write_to_file(filename, b"short").unwrap();
+
+    assert_eq!(std::fs::read_to_string(path).unwrap(), "short");
+}
+
 fn get_output<E: Exporter + Default>(
     results: &[BenchmarkResult],
     unit: Option<Unit>,