Attach an error listener to the upgrade socket in NodeHttpServer

[longtngo]

A peer that resets an HTTP upgrade connection takes the whole Node process down.

Mechanism

Node removes its own listeners from the socket when it emits upgrade and hands the raw socket to the application, and ws only attaches its own once handleUpgrade runs. In makeUpgradeHandler the socket gets a close listener but never an error one, so in that window (and for the entire life of any upgrade request that never completes the handshake) the socket has no error listener at all. Node turns an 'error' event with no listener into an uncaught exception, which exits the process.

const fiber = Fiber.runIn(Effect.runForkWith(context)(handledApp), options.scope)
socket.on("close", () => { ... })   // <- no socket.on("error", ...)

Reproduction

Twenty lines, no application code involved. Server:

import * as NodeHttpServer from "@effect/platform-node/NodeHttpServer"
import * as Effect from "effect/Effect"
import * as HttpServer from "effect/unstable/http/HttpServer"
import * as HttpServerResponse from "effect/unstable/http/HttpServerResponse"
import * as Http from "node:http"

const program = Effect.gen(function*() {
  yield* HttpServer.serveEffect(Effect.succeed(HttpServerResponse.text("ok")))
  yield* Effect.never
}).pipe(
  Effect.provide(NodeHttpServer.layer(() => Http.createServer(), { port: 43111 })),
  Effect.scoped
)

Effect.runFork(program)

Client: open a TCP socket, send an upgrade request, then reset it instead of closing it.

import * as net from "node:net"

const socket = net.connect({ port: 43111, host: "127.0.0.1" }, () => {
  socket.write(
    "GET /ws HTTP/1.1\r\nHost: 127.0.0.1\r\nUpgrade: websocket\r\nConnection: Upgrade\r\n" +
      "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\nSec-WebSocket-Version: 13\r\n\r\n"
  )
  setTimeout(() => socket.resetAndDestroy(), 250)
})
socket.on("error", () => {})

The server process is gone:

node:events:487
      throw er; // Unhandled 'error' event
      ^
Error: read ECONNRESET
    at TCP.onStreamRead (node:internal/stream_base_commons:216:20)
Emitted 'error' event on Socket instance at:
    ...
  errno: -54, code: 'ECONNRESET', syscall: 'read'

This is not a synthetic edge case: it took down a deployed server roughly every one to three minutes (10 process restarts in 30 minutes) as ordinary clients dropped their websockets, a browser tab closing or a phone leaving the network. Instrumenting net.Socket.prototype.emit in the live process named the socket outright: listenerCount('error') === 0 on a GET /ws request with resUpgrade: true.

Fix

Attach a no-op error listener alongside the existing close listener. The connection is already gone by the time this fires, so there is nothing to do but keep the event from going unhandled. The close handler still runs and still interrupts the fiber.

Confirmation that this is the mechanism rather than a correlation: with the listener attached, the same sockets emit the same ECONNRESET at the same rate with unhandled: false, and the process survives. The only variable changed is whether a listener existed.

Test

an upgrade connection reset by the peer does not crash the process drives a real socket against a real port and asserts nothing reached uncaughtException. Without the source change it fails with expected [ Error: read ECONNRESET ] to deeply equal []; with it the file passes 27/27.

BunHttpServer is not affected, since upgrades there go through bunServer.upgrade() rather than a raw Node socket.

[changeset-bot]

🦋 Changeset detected

Latest commit: 0ab2e83

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 30 packages

Name	Type
@effect/platform-node	Patch
effect	Patch
@effect/opentelemetry	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-deno	Patch
@effect/platform-node-shared	Patch
@effect/vitest	Patch
@effect/ai-anthropic	Patch
@effect/ai-openai-compat	Patch
@effect/ai-openai	Patch
@effect/ai-openrouter	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/docgen	Patch
@effect/doctest	Patch
@effect/openapi-generator	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pullfrog]

✅ No new issues found.

Reviewed changes

• Add error listener to upgrade socket — a no-op socket.on("error", () => {}) is added in makeUpgradeHandler alongside the existing close listener, closing the window where a peer reset would turn into an unhandled 'error' event and crash the process.
• Integration test for upgrade connection reset — drives a raw socket with an upgrade request, resets it with resetAndDestroy(), and asserts no uncaughtException reaches the process.
• Patch changeset — correctly scoped to @effect/platform-node.

  ^{｜ View workflow run ｜ Using DeepSeek Pro (free via Pullfrog for OSS) (Kimi K2 not used — the program covers this model; add its provider key to run your pick) ｜ 𝕏}

[github-actions]

Bundle Size Analysis

Generated from PR build output; treat the content below as untrusted.

File Name	Current Size	Previous Size	Difference
basic.ts	7.06 KB	7.06 KB	0.00 KB (0.00%)
batching.ts	9.86 KB	9.86 KB	0.00 KB (0.00%)
brand.ts	6.34 KB	6.34 KB	0.00 KB (0.00%)
cache.ts	10.62 KB	10.62 KB	0.00 KB (0.00%)
config.ts	20.60 KB	20.60 KB	0.00 KB (0.00%)
differ.ts	20.20 KB	20.20 KB	0.00 KB (0.00%)
http-client.ts	21.49 KB	21.49 KB	0.00 KB (0.00%)
logger.ts	10.76 KB	10.76 KB	0.00 KB (0.00%)
metric.ts	8.98 KB	8.98 KB	0.00 KB (0.00%)
optic.ts	7.18 KB	7.18 KB	0.00 KB (0.00%)
pubsub.ts	14.90 KB	14.90 KB	0.00 KB (0.00%)
queue.ts	11.58 KB	11.58 KB	0.00 KB (0.00%)
schedule.ts	10.74 KB	10.74 KB	0.00 KB (0.00%)
schema-class.ts	19.14 KB	19.14 KB	0.00 KB (0.00%)
schema-fromJsonSchemaDocument.ts	28.96 KB	28.96 KB	0.00 KB (0.00%)
schema-representation-roundtrip.ts	25.29 KB	25.29 KB	0.00 KB (0.00%)
schema-string-transformation.ts	13.30 KB	13.30 KB	0.00 KB (0.00%)
schema-string.ts	10.94 KB	10.94 KB	0.00 KB (0.00%)
schema-template-literal.ts	15.17 KB	15.17 KB	0.00 KB (0.00%)
schema-toArbitraryLazy.ts	21.94 KB	21.94 KB	0.00 KB (0.00%)
schema-toCodeDocument.ts	24.34 KB	24.34 KB	0.00 KB (0.00%)
schema-toCodecJson.ts	19.18 KB	19.18 KB	0.00 KB (0.00%)
schema-toEquivalence.ts	19.01 KB	19.01 KB	0.00 KB (0.00%)
schema-toFormatter.ts	18.87 KB	18.87 KB	0.00 KB (0.00%)
schema-toJsonSchemaDocument.ts	22.60 KB	22.60 KB	0.00 KB (0.00%)
schema-toRepresentation.ts	19.52 KB	19.52 KB	0.00 KB (0.00%)
schema.ts	18.41 KB	18.41 KB	0.00 KB (0.00%)
stm.ts	12.54 KB	12.54 KB	0.00 KB (0.00%)
stream.ts	9.80 KB	9.80 KB	0.00 KB (0.00%)

[pullfrog]

Important

The latest commit fixes the source indentation, but the incremental diff removed the uncaught array declaration from the new test, so the test currently fails at runtime with ReferenceError: uncaught is not defined. That needs to be restored before merge.

Reviewed changes

• Fixed indentation in NodeHttpServer.ts — const fiber and the socket.on("close", ...) lines are now correctly indented after the code-review suggestion.
• Removed explanatory comments and uncaught declaration in the test — the incremental edit trimmed the comments around the uncaughtException listener and deleted const uncaught: Array<unknown> = [], leaving uncaught.push(error) and the assertion expect(uncaught).toEqual([]) referencing an undefined variable.
• Changeset wording tightened — now reads "Stop a reset upgrade connection from crashing the process in NodeHttpServer".

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}

[pullfrog]

✅ No new issues found.

Reviewed changes

• Restored the missing uncaught array declaration in the new upgrade-socket test; the uncaughtException listener and final assertion now reference a defined variable.
• Confirmed the test passes — an upgrade connection reset by the peer does not crash the process runs successfully.
• No source-code changes in this delta beyond the already-reviewed socket.on("error", () => {}) addition.

  ^{｜ View workflow run ｜ Using Kimi K2 (free via Pullfrog for OSS) ｜ 𝕏}