onConnectTimeout bug

[zabranskiy]

Bug Description

[error] uncaughtException TypeError: Cannot read properties of undefined (reading 'autoSelectFamilyAttemptedAddresses') at onConnectTimeout (/usr/lib/node_modules/.../node_modules/undici/lib/core/connect.js:224:28) at Immediate.<anonymous> (/usr/lib/node_modules/.../node_modules/undici/lib/core/connect.js:206:11) at process.processImmediate (node:internal/timers:491:21)

undici/lib/core/connect.js file has function onConnectTimeout:

function onConnectTimeout (socket, opts) {
  let message = 'Connect Timeout Error'
  if (Array.isArray(socket.autoSelectFamilyAttemptedAddresses)) { <-- bug in this line
  ...
}

socket is undefined when the garbage collector has already freed the WeakRef, which leads to TypeError.

Reproducible By

It happens rarely on our prod.

Expected Behavior

No error.

Environment

Debian 12
nodejs 22.9.0
undici 6.20.0

[KhafraDev]

#3751

[murrayee]

+1
Is there a solution?

[murrayee]

or how do I catch it？

[KhafraDev]

@murrayee do you have a reproducible sample of code?

[SolT31]

Faced the same issue. Created a MR.