Unhandled rejection ClientDestroyedError when using Agent with clientTtl #4806
Description
Bug Description
When using an Agent with the clientTtl option, under certain conditions, an uncatchable ClientDestroyedError will be thrown.
Reproducible By
const undici = require('undici');
const tp = require('node:timers/promises');
async function main() {
const clientTtl = 1000;
const agent = new undici.Agent({ clientTtl });
console.log('request 1')
const resp = await undici.request("https://example.com", {
dispatcher: agent
});
console.log(resp.statusCode);
// do not consume or destroy the response body here
await tp.setTimeout(clientTtl * 2);
console.log('request 2')
const resp1 = await undici.request("https://example.com", {
dispatcher: agent
});
console.log(resp1.statusCode);
}
process.on('unhandledRejection', (e) => {
console.log('unhandled rejection', e)
})
void main();Output:
request 1
200
request 2
unhandled rejection ClientDestroyedError: The client is destroyed
at Client.close (/tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:52:19)
at /tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:41:14
at new Promise (<anonymous>)
at Client.close (/tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:40:14)
at [close] (/tmp/test/node_modules/undici/lib/dispatcher/pool-base.js:124:41)
at Pool.close (/tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:79:17)
at /tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:41:14
at new Promise (<anonymous>)
at Pool.close (/tmp/test/node_modules/undici/lib/dispatcher/dispatcher-base.js:40:14)
at closeClientIfUnused (/tmp/test/node_modules/undici/lib/dispatcher/agent.js:95:31) {
code: 'UND_ERR_DESTROYED'
}
200
Expected Behavior
There should not be any error.
Environment
Node v24.13.0
Undici 7.20.0
Additional context
- In fix: memory leak in Agent #4425 I made the change to close the client (
Poolby default) when it's no longer used. However, theclientTtloption isn't considered, which means the pool will always be destroyed when it stops having an active connection. - In
Pool.[kGetDispatcher], the client is removed from the Pool if it has been alive for too long. InPoolBase.[kRemoveClient], the client is only removed from the pool's client list in the callback. IfPoolBase.[kClose]gets called after the client is destroyed but before the callback happens, the client will be closed again, triggering this issue.