From c27f0b7c1c421f8300be988d7e488c142716baed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Doeraene?= <sjrdoeraene@gmail.com>
Date: Tue, 2 Nov 2021 17:13:09 +0100
Subject: [PATCH] Fix #12: Force the server and client of Node.js Com to use
 IPv4.

Node.js 17 switched from resolving host names to IPv4 by default to
resolving to the order given by the OS. This was an intended change
done in https://github.com/nodejs/node/pull/39987, which
nevertheless caused issues in downstream projects, as reported in
https://github.com/nodejs/node/issues/40537.

scalajs-env-nodejs hit that issue, as the JVM server opened on IPv4
by default (apparently this is what the JVM does), but the client
tried to connect via IPv6 with Node.js 17. We fix the issue by
forcing the use of IPv4 in the Node.js client, as well as on the
JVM server for good measure.
---
 .github/workflows/ci.yml                              | 11 +++++++++++
 .../scala/org/scalajs/jsenv/nodejs/ComSupport.scala   |  4 ++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 05a925c..2e9e769 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,13 +12,24 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        nodejsversion: ["15"]
         scalaversion: ["2.11.12", "2.12.11", "2.13.2"]
         project: ["scalajs-js-envs", "scalajs-js-envs-test-kit", "scalajs-env-nodejs"]
+        include:
+          - nodejsversion: "16"
+            scalaversion: "2.12.11"
+            project: "scalajs-env-nodejs"
+          - nodejsversion: "17"
+            scalaversion: "2.12.11"
+            project: "scalajs-env-nodejs"
     steps:
       - uses: actions/checkout@v2
       - uses: olafurpg/setup-scala@v10
         with:
           java-version: "adopt@1.8"
+      - uses: actions/setup-node@v2
+        with:
+          node-version: "${{ matrix.nodejsversion }}"
       - uses: coursier/cache-action@v5
       - name: Test
         run: sbt "++${{ matrix.scalaversion }}" ${{ matrix.project }}/test
diff --git a/nodejs-env/src/main/scala/org/scalajs/jsenv/nodejs/ComSupport.scala b/nodejs-env/src/main/scala/org/scalajs/jsenv/nodejs/ComSupport.scala
index 31b514f..bef71ec 100644
--- a/nodejs-env/src/main/scala/org/scalajs/jsenv/nodejs/ComSupport.scala
+++ b/nodejs-env/src/main/scala/org/scalajs/jsenv/nodejs/ComSupport.scala
@@ -209,7 +209,7 @@ object ComRun {
   def start(config: RunConfig, onMessage: String => Unit)(startRun: Path => JSRun): JSComRun = {
     try {
       val serverSocket =
-        new ServerSocket(0, 0, InetAddress.getByName(null)) // Loopback address
+        new ServerSocket(0, 0, InetAddress.getByName("127.0.0.1")) // IPv4 loopback address
 
       val run = startRun(setupFile(serverSocket.getLocalPort))
 
@@ -248,7 +248,7 @@ object ComRun {
         s"""
            |(function() {
            |  // The socket for communication
-           |  var socket = require('net').connect($port);
+           |  var socket = require('net').connect($port, '127.0.0.1'); // IPv4 loopback address
            |
            |  // Buffers received data
            |  var inBuffer = Buffer.alloc(0);