Fix edgecase with socketpair() impacting shell and spawn (#15725)

scripts/runner.node.mjs

@@ -26,7 +26,7 @@ import {
   getBuildUrl,
   getEnv,
   getFileUrl,
-  getLoggedInUserCount,
+  getLoggedInUserCountOrDetails,
   getShell,
   getWindowsExitReason,
   isBuildkite,
@@ -1499,7 +1499,7 @@ export async function main() {
 
   let waitForUser = false;
   while (isCI) {
-    const userCount = getLoggedInUserCount();
+    const userCount = getLoggedInUserCountOrDetails();
     if (!userCount) {
       if (waitForUser) {
         !isQuiet && console.log("No users logged in, exiting runner...");
@@ -1509,7 +1509,11 @@ export async function main() {
 
     if (!waitForUser) {
       startGroup("Summary");
-      console.warn(`Found ${userCount} users logged in, keeping the runner alive until logout...`);
+      if (typeof userCount === "number") {
+        console.warn(`Found ${userCount} users logged in, keeping the runner alive until logout...`);
+      } else {
+        console.warn(userCount);
+      }
       waitForUser = true;
     }
 

scripts/utils.mjs

@@ -2688,7 +2688,7 @@ export function printEnvironment() {
 /**
  * @returns {number | undefined}
  */
-export function getLoggedInUserCount() {
+export function getLoggedInUserCountOrDetails() {
   if (isWindows) {
     const pwsh = which(["pwsh", "powershell"]);
     if (pwsh) {
@@ -2705,7 +2705,31 @@ export function getLoggedInUserCount() {
 
   const { error, stdout } = spawnSync(["who"]);
   if (!error) {
-    return stdout.split("\n").filter(line => /tty|pts/i.test(line)).length;
+    const users = stdout
+      .split("\n")
+      .filter(line => /tty|pts/i.test(line))
+      .map(line => {
+        // who output format: username terminal date/time (ip)
+        const [username, terminal, datetime, ip] = line.split(/\s+/);
+        return {
+          username,
+          terminal,
+          datetime,
+          ip: (ip || "").replace(/[()]/g, ""), // Remove parentheses from IP
+        };
+      });
+
+    if (users.length === 0) {
+      return 0;
+    }
+
+    let message = users.length + " currently logged in users:";
+
+    for (const user of users) {
+      message += `\n- ${user.username} on ${user.terminal} since ${user.datetime}${user.ip ? ` from ${user.ip}` : ""}`;
+    }
+
+    return message;
   }
 }