Studio cannot save or delete legal long paths because backup filenames exceed filesystem limits #6610

import { createServer } from 'node:http';
import { once } from 'node:events';
import { mkdtempSync, readFileSync, existsSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import { pathToFileURL } from 'node:url';

const { createStudioApi } = await import(pathToFileURL(join(process.cwd(), 'packages/studio-server/dist/index.js')));
const projectDir = mkdtempSync(join(tmpdir(), 'hf-file-operations-repro-'));
const project = { id: 'demo', dir: projectDir };
const unavailable = () => { throw new Error('Unexpected unrelated adapter call'); };
const api = createStudioApi({
  listProjects: () => [project],
  resolveProject: id => id === 'demo' ? project : null,
  bundle: unavailable,
  lint: unavailable,
  runtimeUrl: '/runtime.js',
  rendersDir: unavailable,
  startRender: unavailable,
});
const server = createServer(async (req, res) => {
  try {
    const chunks = [];
    for await (const chunk of req) chunks.push(chunk);
    const response = await api.fetch(new Request(`http://${req.headers.host}${req.url}`, {
      method: req.method,
      headers: req.headers,
      ...(chunks.length ? { body: Buffer.concat(chunks) } : {}),
    }));
    res.writeHead(response.status, Object.fromEntries(response.headers));
    res.end(Buffer.from(await response.arrayBuffer()));
  } catch (error) {
    res.writeHead(500);
    res.end(String(error));
  }
});
server.listen(0, '127.0.0.1');
await once(server, 'listening');
const origin = `http://127.0.0.1:${server.address().port}`;
const request = async (path, init) => {
  const response = await fetch(`${origin}/projects/demo/${path}`, init);
  return { status: response.status, body: await response.json() };
};
const longPath = 'campaigns/2026/autumn-product-launch/client-review/round-03/approved-deliverables/social-media/vertical/english-united-kingdom/subtitles-enabled/product-onboarding/introduction.txt';
try {
  const url = `files/${longPath}`;
  const created = await request(url, { method: 'POST', body: 'before' });
  const opened = await request(url);
  const saved = await request(url, { method: 'PUT', headers: { 'If-Match': opened.body.version }, body: 'after' });
  const afterSave = readFileSync(join(projectDir, longPath), 'utf8');
  const saveBackup = saved.body.backupPath ? readFileSync(join(projectDir, saved.body.backupPath), 'utf8') : null;
  const deleted = await request(url, { method: 'DELETE' });
  const deleteBackup = deleted.body.backupPath ? readFileSync(join(projectDir, deleted.body.backupPath), 'utf8') : null;
  const result = { projectDir, longPath, pathBytes: Buffer.byteLength(longPath), created, opened, saved, afterSave, saveBackup, deleted, existsAfterDelete: existsSync(join(projectDir, longPath)), deleteBackup };
  console.log(JSON.stringify(result, null, 2));
} finally {
  server.closeAllConnections();
  await new Promise(resolve => server.close(resolve));
}