net: enable autoSelectFamily by default

doc/api/cli.md

@@ -314,14 +314,14 @@ added: v6.0.0
 Enable FIPS-compliant crypto at startup. (Requires Node.js to be built
 against FIPS-compatible OpenSSL.)
 
-### `--enable-network-family-autoselection`
+### `--no-network-family-autoselection`
 
 <!-- YAML
 added: v19.4.0
 -->
 
-Enables the family autoselection algorithm unless connection options explicitly
-disables it.
+Disables the family autoselection algorithm unless connection options explicitly
+enables it.
 
 ### `--enable-source-maps`
 
@@ -1888,7 +1888,6 @@ Node.js options that are allowed are:
 * `--disable-proto`
 * `--dns-result-order`
 * `--enable-fips`
-* `--enable-network-family-autoselection`
 * `--enable-source-maps`
 * `--experimental-abortcontroller`
 * `--experimental-import-meta-resolve`
@@ -1929,6 +1928,7 @@ Node.js options that are allowed are:
 * `--no-extra-info-on-fatal-exception`
 * `--no-force-async-hooks-checks`
 * `--no-global-search-paths`
+* `--no-network-family-autoselection`
 * `--no-warnings`
 * `--node-memory-debug`
 * `--openssl-config`

doc/api/net.md

@@ -870,6 +870,11 @@ behavior.
 <!-- YAML
 added: v0.1.90
 changes:
+  - version: REPLACEME
+    pr-url: REPLACEME
+    description: The default value for autoSelectFamily option is now true.
+                 The `--enable-network-family-autoselection` has been removed
+                 in favor of `--network-family-autoselection`.
   - version: v19.4.0
     pr-url: https://github.com/nodejs/node/pull/45777
     description: The default value for autoSelectFamily option can be changed
@@ -936,8 +941,8 @@ For TCP connections, available `options` are:
   option before timing out and trying the next address.
   Ignored if the `family` option is not `0` or if `localAddress` is set.
   Connection errors are not emitted if at least one connection succeeds.
-  **Default:** initially `false`, but it can be changed at runtime using [`net.setDefaultAutoSelectFamily(value)`][]
-  or via the command line option `--enable-network-family-autoselection`.
+  **Default:** initially `true`, but it can be changed at runtime using [`net.setDefaultAutoSelectFamily(value)`][]
+  or via the command line option `--no-network-family-autoselection`.
 * `autoSelectFamilyAttemptTimeout` {number}: The amount of time in milliseconds to wait
   for a connection attempt to finish before trying the next address when using the `autoSelectFamily` option.
   If set to a positive integer less than `10`, then the value `10` will be used instead.

lib/net.js

@@ -126,7 +126,7 @@ let cluster;
 let dns;
 let BlockList;
 let SocketAddress;
-let autoSelectFamilyDefault = getOptionValue('--enable-network-family-autoselection');
+let autoSelectFamilyDefault = getOptionValue('--network-family-autoselection');
 
 const { clearTimeout, setTimeout } = require('timers');
 const { kTimeout } = require('internal/timers');

src/node_options.cc

@@ -353,10 +353,11 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             "returned)",
             &EnvironmentOptions::dns_result_order,
             kAllowedInEnvvar);
-  AddOption("--enable-network-family-autoselection",
-            "Enable network address family autodetection algorithm",
-            &EnvironmentOptions::enable_network_family_autoselection,
-            kAllowedInEnvvar);
+  AddOption("--network-family-autoselection",
+            "Disable network address family autodetection algorithm",
+            &EnvironmentOptions::network_family_autoselection,
+            kAllowedInEnvvar,
+            true);
   AddOption("--enable-source-maps",
             "Source Map V3 support for stack traces",
             &EnvironmentOptions::enable_source_maps,

src/node_options.h

@@ -127,7 +127,7 @@ class EnvironmentOptions : public Options {
   bool frozen_intrinsics = false;
   int64_t heap_snapshot_near_heap_limit = 0;
   std::string heap_snapshot_signal;
-  bool enable_network_family_autoselection = false;
+  bool network_family_autoselection = true;
   uint64_t max_http_header_size = 16 * 1024;
   bool deprecation = true;
   bool force_async_hooks_checks = true;

test/parallel/test-net-autoselectfamily-commandline-option.js

@@ -1,6 +1,6 @@
 'use strict';
 
-// Flags: --enable-network-family-autoselection
+// Flags: --no-network-family-autoselection
 
 const common = require('../common');
 const { parseDNSPacket, writeDNSPacket } = require('../common/dns');
@@ -10,13 +10,7 @@ const dgram = require('dgram');
 const { Resolver } = require('dns');
 const { createConnection, createServer } = require('net');
 
-// Test that happy eyeballs algorithm can be enable from command line.
-
-let autoSelectFamilyAttemptTimeout = common.platformTimeout(250);
-if (common.isWindows) {
-  // Some of the windows machines in the CI need more time to establish connection
-  autoSelectFamilyAttemptTimeout = common.platformTimeout(1500);
-}
+// Test that happy eyeballs algorithm can be disabled from command line.
 
 function _lookup(resolver, hostname, options, cb) {
   resolver.resolve(hostname, 'ANY', (err, replies) => {
@@ -65,7 +59,7 @@ function createDnsServer(ipv6Addr, ipv4Addr, cb) {
   });
 }
 
-// Test that IPV4 is reached if IPV6 is not reachable
+// Test that IPV4 is NOT reached if IPV6 is not reachable and the option has been disabled via command line
 {
   createDnsServer('::1', '127.0.0.1', common.mustCall(function({ dnsServer, lookup }) {
     const ipv4Server = createServer((socket) => {
@@ -80,29 +74,25 @@ function createDnsServer(ipv6Addr, ipv4Addr, cb) {
 
       const connection = createConnection({
         host: 'example.org',
-        port: port,
+        port,
         lookup,
-        autoSelectFamilyAttemptTimeout,
       });
 
-      let response = '';
-      connection.setEncoding('utf-8');
-
-      connection.on('ready', common.mustCall(() => {
-        assert.deepStrictEqual(connection.autoSelectFamilyAttemptedAddresses, [`::1:${port}`, `127.0.0.1:${port}`]);
-      }));
+      connection.on('ready', common.mustNotCall());
+      connection.on('error', common.mustCall((error) => {
+        assert.strictEqual(connection.autoSelectFamilyAttemptedAddresses, undefined);
 
-      connection.on('data', (chunk) => {
-        response += chunk;
-      });
+        if (common.hasIPv6) {
+          assert.strictEqual(error.code, 'ECONNREFUSED');
+          assert.strictEqual(error.message, `connect ECONNREFUSED ::1:${port}`);
+        } else {
+          assert.strictEqual(error.code, 'EADDRNOTAVAIL');
+          assert.strictEqual(error.message, `connect EADDRNOTAVAIL ::1:${port} - Local (:::0)`);
+        }
 
-      connection.on('end', common.mustCall(() => {
-        assert.strictEqual(response, 'response-ipv4');
         ipv4Server.close();
         dnsServer.close();
       }));
-
-      connection.write('request');
     }));
   }));
 }