Electron ASAR CopyFileOut stale temporary-path cache reproduction

main.js

const { app } = require('electron');
const asar = require('@electron/asar');
const fs = require('node:fs');
const os = require('node:os');
const path = require('node:path');

const marker = 'electron-asar-stale-cache-repro-7e8fa4f9\n';

function readStream(file) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    fs.createReadStream(file)
      .on('data', (chunk) => chunks.push(chunk))
      .once('error', reject)
      .once('end', () => resolve(Buffer.concat(chunks).toString()));
  });
}

function findExtractedCopy() {
  for (const name of fs.readdirSync(os.tmpdir())) {
    const candidate = path.join(os.tmpdir(), name);
    try {
      if (fs.statSync(candidate).isFile() && fs.readFileSync(candidate, 'utf8') === marker) {
        return candidate;
      }
    } catch {
      // Ignore unrelated temporary entries that disappear or cannot be read.
    }
  }
  return null;
}

app.whenReady().then(async () => {
  const fixtureDirectory = path.join(__dirname, 'fixture');
  const archive = path.join(__dirname, 'fixture.asar');
  const packedFile = path.join(archive, 'payload.txt');
  fs.mkdirSync(fixtureDirectory, { recursive: true });
  fs.writeFileSync(path.join(fixtureDirectory, 'payload.txt'), marker);
  await asar.createPackage(fixtureDirectory, archive);

  const first = await readStream(packedFile);
  if (first !== marker) throw new Error('First ASAR stream returned unexpected data');

  const extracted = findExtractedCopy();
  if (!extracted) throw new Error('Could not locate the extracted temporary copy');
  console.log(`Extracted copy: ${extracted}`);
  fs.unlinkSync(extracted);
  console.log('Deleted the extracted copy while Electron remains running.');

  // Buffer reads still work because they read packed bytes from the archive.
  console.log(`readFileSync after deletion: ${JSON.stringify(fs.readFileSync(packedFile, 'utf8'))}`);

  try {
    await readStream(packedFile);
    console.error('UNEXPECTED: second createReadStream succeeded');
    process.exitCode = 2;
  } catch (error) {
    console.log(`REPRODUCED: ${error.code} opening cached path ${error.path}`);
    process.exitCode = error.code === 'ENOENT' && error.path === extracted ? 0 : 3;
  } finally {
    app.quit();
  }
}).catch((error) => {
  console.error(error);
  process.exitCode = 1;
  app.quit();
});

package.json

{
  "name": "electron-asar-stale-copyfileout-cache-repro",
  "version": "1.0.0",
  "private": true,
  "main": "main.js",
  "scripts": {
    "start": "electron ."
  },
  "devDependencies": {
    "@electron/asar": "latest",
    "electron": "43.4.0"
  }
}

See:

• electron/electron#52804