FIX: writeFileSafelyの一時ファイルが既存のファイルを上書きしないようにする

src/backend/electron/fileHelper.ts

@@ -1,4 +1,5 @@
 import fs from "fs";
+import log from "electron-log/main";
 import { moveFileSync } from "move-file";
 
 /**
@@ -9,10 +10,34 @@ export function writeFileSafely(
   path: string,
   data: string | NodeJS.ArrayBufferView,
 ) {
-  const tmpPath = `${path}.tmp`;
-  fs.writeFileSync(tmpPath, data);
+  let tmpPath: string;
+  let maxRetries = 16;
+  while (true) {
+    maxRetries--;
+    try {
+      // ランダムな文字列を8文字生成
+      const randStr = Math.floor(Math.random() * 36 ** 8)
+        .toString(36)
+        .padStart(8, "0");
+      tmpPath = `${path}-${randStr}.tmp`;
+      fs.writeFileSync(tmpPath, data, { flag: "wx" });
+      break;
+    } catch (error) {
+      const e = error as NodeJS.ErrnoException;
+      if (e.code !== "EEXIST" || maxRetries <= 0) {
+        throw e;
+      }
+    }
+  }
 
-  moveFileSync(tmpPath, path, {
-    overwrite: true,
-  });
+  try {
+    moveFileSync(tmpPath, path, {
+      overwrite: true,
+    });
+  } catch (error) {
+    fs.promises.unlink(tmpPath).catch((reason) => {
+      log.warn("Fail to remove %s\n  %o", tmpPath, reason);
+    });
+    throw error;
+  }
 }