What causes "spawnSync is not supported in Cloudflare Workers" in DIYgod/RSSHub?

Remove the spawnSync code path under Workers.

spawnSync is not supported in Cloudflare Workers

Error message

spawnSync is not supported in Cloudflare Workers

What it means

Inline child_process.spawnSync() in lib/shims/node-module.ts throws. Synchronous subprocess spawning is impossible in the Workers runtime; spawnSync joins the other hard-fail spawn-family members. Only execSync is given an empty-Buffer stub.

Source

Thrown at lib/shims/node-module.ts:99

const child_process = {
    execSync: (_command: string): Buffer => Buffer.from(''),
    exec: () => {
        throw new Error('exec is not supported in Cloudflare Workers');
    },
    spawn: () => {
        throw new Error('spawn is not supported in Cloudflare Workers');
    },
    fork: () => {
        throw new Error('fork is not supported in Cloudflare Workers');
    },
    execFile: () => {
        throw new Error('execFile is not supported in Cloudflare Workers');
    },
    execFileSync: () => {
        throw new Error('execFileSync is not supported in Cloudflare Workers');
    },
    spawnSync: () => {
        throw new Error('spawnSync is not supported in Cloudflare Workers');
    },
};

// Create a CJS-compatible events module
// In CJS, require('events') returns EventEmitter class directly (the default export)
// but also has named exports attached to it
const eventsModule = Object.assign(events, eventsNamespace);

// Map of module names to their exports
const builtinModules: Record<string, unknown> = {
    fs,
    path,

    util,
    stream,
    events: eventsModule,
    buffer,
    crypto,

View on GitHub (pinned to bed535e087)

Solutions

Remove the spawnSync code path under Workers.
Use execSync's no-op stub pattern if a generic command and degraded empty result are acceptable.
Run on Node.

Example fix

// before
require('child_process').spawnSync('git', ['rev-parse', 'HEAD']);
// after
require('child_process').execSync('git rev-parse HEAD'); // returns '' under Workers

Defensive patterns

Strategy: validation

Validate before calling

const isNode = typeof process !== 'undefined' && !!process.versions?.node;
if (!isNode) {
  // Workers: spawnSync throws — use execSync (stubbed) or remove the probe
}

Type guard

function isWorkersShimError(e: unknown): e is Error {
  return e instanceof Error && /not supported in Cloudflare Workers/.test(e.message);
}

Try / catch

try {
  if (isNode) return require('child_process').spawnSync(bin, args);
  return { stdout: Buffer.from('') };
} catch (e) {
  if (isWorkersShimError(e)) return { stdout: Buffer.from('') };
  throw e;
}

Prevention

Use execSync (stubbed to empty) instead of spawnSync under Workers where possible.
Remove synchronous binary probes from Worker paths.
Run spawnSync-dependent logic on Node.

When it happens

Trigger: A CJS dependency reached via createRequire that calls child_process.spawnSync(bin, args) under Workers.

Common situations: Synchronous binary probes; libraries that block on a subprocess result.

Related errors

AI-assisted analysis of DIYgod/RSSHub@bed535e087 (2026-08-12). Data as JSON: /api/errors/4dafe547ed2a67ea. Report an issue: GitHub.