Work around qemu/emulator port conflicts by using `net.createConnecti…

…on` instead of `net.createServer`

changelog.md

@@ -2,12 +2,17 @@
 
 ---
 
-## [5.8.4] 2023-10-23
+## [5.8.4 - 5.8.5] 2023-10-23
 
 ### Added
 
 - Added support for hydration of platform-specific binary deps (namely: Python); fixes #1457
 
+
+### Fixed
+
+- Fixed issue where qemu/emulator port conflicts were not detected with our open port tester; fixes 1441
+
 ---
 
 ## [5.8.3] 2023-10-17

src/sandbox/ports.js

@@ -71,36 +71,38 @@ module.exports = function getPorts (params, callback) {
  */
 function checkPort (checking, ports, name, single, callback) {
   let tries = 0
-  let tester = net.createServer()
   let done = false
   function check () {
     if (tries === 50) {
       let msg = `Could not find open port after 50 tries, please close some applications and try again`
       return callback(Error(msg))
     }
-    tester.listen(checking)
-    tester.once('error', err => {
-      if (err.message.includes('EADDRINUSE')) {
-        if (single) {
-          return callback(Error(`Port ${checking} (${name}) is already in use, please select another with prefs.arc\nSee https://arc.codes/docs/en/reference/configuration/local-preferences#ports---list for config`))
-        }
-        else {
-          tries++
-          checking++
-          return check()
-        }
+    let client = net.createConnection({ port: checking }, () => {
+      if (single) {
+        return callback(Error(`Port ${checking} (${name}) is already in use, please select another with prefs.arc\nSee https://arc.codes/docs/en/reference/configuration/local-preferences#ports---list for config`))
+      }
+      else {
+        tries++
+        checking++
+        return client.end(check)
       }
     })
-    tester.once('listening', () => {
-      tester.close(() => {
-        // Tester close emits multiple events, so only call back once
-        if (!done) {
-          done = true
-          if (Object.values(ports).includes(checking)) {
-            return callback(Error(`Port conflict found on ${checking}, please specify another port`))
+    client.once('error', err => {
+      client.end(() => {
+        if (err.code === 'ECONNREFUSED') {
+          // Tester close emits multiple events, so only call back once
+          if (!done) {
+            done = true
+            if (Object.values(ports).includes(checking)) {
+              return callback(Error(`Port conflict found on ${checking}, please specify another port`))
+            }
+            ports[name] = checking
+            callback()
           }
-          ports[name] = checking
-          callback()
+        }
+        else {
+          console.error(`Unknown port checking error`)
+          return callback(err)
         }
       })
     })