fix: race condition in writeStats (#711)

* fix: race condition in `writeStats`

* docs: add changelog entry for #711

Author: colinaaa

CHANGELOG.md

@@ -12,6 +12,9 @@ _Note: Gaps between patch versions are faulty, broken or test releases._
 
 ## UNRELEASED
 
+* **Bug Fix**
+  * Fix a race condition in `writeStats` that could lead to incorrect content in `stats.json` ([#711](https://github.com/webpack/webpack-bundle-analyzer/pull/711) by [@colinaaa](https://github.com/colinaaa))
+
 ## 5.2.0
 
 * **New Feature**

src/statsUtils.js

@@ -1,5 +1,6 @@
 const { createWriteStream } = require("node:fs");
 const { Readable } = require("node:stream");
+const { pipeline } = require("node:stream/promises");
 
 /** @typedef {import("./BundleAnalyzerPlugin").EXPECTED_ANY} EXPECTED_ANY */
 /** @typedef {import("webpack").StatsCompilation} StatsCompilation */
@@ -91,12 +92,7 @@ class StatsSerializeStream extends Readable {
  * @returns {Promise<void>}
  */
 async function writeStats(stats, filepath) {
-  return new Promise((resolve, reject) => {
-    new StatsSerializeStream(stats)
-      .on("end", resolve)
-      .on("error", reject)
-      .pipe(createWriteStream(filepath));
-  });
+  await pipeline(new StatsSerializeStream(stats), createWriteStream(filepath));
 }
 
 module.exports = { StatsSerializeStream, writeStats };

test/statsUtils.js

@@ -1,7 +1,7 @@
 const { readFileSync } = require("node:fs");
 const path = require("node:path");
 const { globSync } = require("tinyglobby");
-const { StatsSerializeStream } = require("../src/statsUtils");
+const { StatsSerializeStream, writeStats } = require("../src/statsUtils");
 
 async function stringify(json) {
   return new Promise((resolve, reject) => {
@@ -78,3 +78,16 @@ describe("StatsSerializeStream", () => {
     });
   }
 });
+
+describe("writeStats", () => {
+  it("should fail gracefully if writing to a non-existent directory", async () => {
+    const nonExistentPath = path.join(
+      __dirname,
+      "non-existent-dir",
+      "stats.json",
+    );
+    await expect(
+      writeStats({ foo: "bar" }, nonExistentPath),
+    ).rejects.toMatchObject({ code: "ENOENT" });
+  });
+});