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node-red-node-email: uncaught TypeError 'fetchCache' in imap crashes the Node-RED runtime

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Evaluación

Dificultad
3/5
Tiempo estimado
1-2 días
Aptitud para principiantes
42/100
Tipo de issue
Error
Claridad
Bastante claro
Estado de actividad
Activo
Stack tecnológico
javascript, nodejs
Área
backend

Línea de trabajo

The crash comes from the bundled imap dependency at node_modules/node-red-node-email/node_modules/imap/lib/Connection.js, around lines 196-197, where the 'body' handler reads self._curReq.fetchCache without checking _curReq. Start by reading that handler and the Parser callbacks the stack trace names. Done means an unsolicited FETCH body is drained and ignored without throwing, and the maintainers have agreed whether the fix goes in as a guard, a patch, or a dependency change.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

Which node are you reporting and issue on?

node-red-node-email (e-mail in, IMAP)

What are the steps to reproduce?

Add an e-mail in node with this configuration:

Protocol: IMAP, server imap.gmail.com, port 993, SSL on, Start TLS: never, Auth: Basic
Folder: INBOX, Criteria: UNSEEN, Disposition: None
Fetch: automatically, every 420 s

Deploy and leave it running.
After some time, Node-RED crashes. It happens intermittently, after several hours of polling.

What happens?

An uncaught exception inside the bundled imap dependency stops the whole Node-RED process, not just the node:

[red] Uncaught Exception:
[error] TypeError: Cannot read properties of undefined (reading 'fetchCache')
    at Parser.<anonymous> (/data/node_modules/node-red-node-email/node_modules/imap/lib/Connection.js:197:28)
    at Parser.emit (node:events:514:28)
    at Parser._resUntagged (/data/node_modules/node-red-node-email/node_modules/imap/lib/Parser.js:196:10)
    at Parser._parse (/data/node_modules/node-red-node-email/node_modules/imap/lib/Parser.js:137:16)
    at Parser._tryread (/data/node_modules/node-red-node-email/node_modules/imap/lib/Parser.js:82:15)
    at Parser._cbReadable (/data/node_modules/node-red-node-email/node_modules/imap/lib/Parser.js:53:12)
    at TLSSocket.emit (node:events:514:28)
    at emitReadable_ (node:internal/streams/readable:845:12)
    at process.processTicksAndRejections (node:internal/process/task_queues:89:21)

Root cause: [email protected], which this package pins, has this code in lib/Connection.js:196-197:

parser.on('body', function(stream, info) {
  var msg = self._curReq.fetchCache[info.seqno], toget;

The server can send an untagged FETCH that carries a body literal when no command is in flight, so self._curReq is undefined. This happens with Gmail after a fetch completed, timed out, or the connection was re-established. The handler does not check _curReq, and the error is thrown inside a TLSSocket read callback. An imap.on('error') listener therefore cannot catch it, and Node-RED treats it as an uncaught exception. imap (mscdex/node-imap) has not been released since 2016, so a fix upstream is unlikely.

Proposed fix (low risk): guard the handler. Drain the stray literal so the parser stays in sync, then drop it:

parser.on('body', function(stream, info) {
  if (!self._curReq || !self._curReq.fetchCache) {
    stream.resume(); // unsolicited FETCH body: consume and ignore
    return;
  }
  var msg = self._curReq.fetchCache[info.seqno], toget;

The fix could ship either by applying the guard with patch-package in postinstall, or by switching the dependency to a maintained fork of imap that already guards _curReq. A longer-term option is to migrate the IMAP input to imapflow. It is maintained and reports protocol errors as promise rejections instead of throwing from socket callbacks.

Workaround: apply the guard by hand in node_modules/node-red-node-email/node_modules/imap/lib/Connection.js and restart Node-RED. The change is lost on every reinstall.

What did you expect to happen?

An unexpected server response should at most raise a node error or status, and the node should reconnect. It should never take down the runtime and every other flow running in it.

Example flow
paste your flow here
Environment
  • Node-RED version: 5.0.8 (official docker container)
    node -v && npm -v
    v24.21.0
    11.21.0
  • Platform/OS: Docker, official nodered/node-red image
  • Browser: n/a (runtime crash)
  • node-red-node-email version: node-red-node-email 5.2.5
  • imap version: 0.8.19
  • IMAP server: imap.gmail.com:993
Lenguaje dominante
JavaScript
Estrellas
1.1k
Forks
610
Merge medio
1 d 4 h
PR fusionados (30 d)
2

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  4. Abre un pull request que haga referencia al número del issue.

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