lib,test: fix bug in InternalSocketAddress

lib/internal/socketaddress.js

@@ -142,6 +142,12 @@ class InternalSocketAddress extends JSTransferable {
   constructor(handle) {
     super();
     this[kHandle] = handle;
+    this[kDetail] = this[kHandle]?.detail({
+      address: undefined,
+      port: undefined,
+      family: undefined,
+      flowlabel: undefined,
+    });
   }
 }
 

test/parallel/test-socketaddress.js

@@ -1,3 +1,4 @@
+// Flags: --expose-internals
 'use strict';
 
 const common = require('../common');
@@ -10,6 +11,15 @@ const {
   SocketAddress,
 } = require('net');
 
+const {
+  InternalSocketAddress,
+} = require('internal/socketaddress');
+const { internalBinding } = require('internal/test/binding');
+const {
+  SocketAddress: _SocketAddress,
+  AF_INET
+} = internalBinding('block_list');
+
 {
   const sa = new SocketAddress();
   strictEqual(sa.address, '127.0.0.1');
@@ -108,3 +118,20 @@ const {
 throws(() => new SocketAddress({ flowlabel: -1 }), {
   code: 'ERR_OUT_OF_RANGE'
 });
+
+{
+  // Test that the internal helper class InternalSocketAddress correctly
+  // inherits from SocketAddress and that it does not throw when its properties
+  // are accessed.
+
+  const address = '127.0.0.1';
+  const port = 8080;
+  const flowlabel = 0;
+  const handle = new _SocketAddress(address, port, AF_INET, flowlabel);
+  const addr = new InternalSocketAddress(handle);
+  ok(addr instanceof SocketAddress);
+  strictEqual(addr.address, address);
+  strictEqual(addr.port, port);
+  strictEqual(addr.family, 'ipv4');
+  strictEqual(addr.flowlabel, flowlabel);
+}