swarm-ui: only the newest start's late stop ends a claude login

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.tsx

@@ -16,7 +16,9 @@ import { TextField } from "../../ui/text-field/TextField.js";
 import {
   afterCode,
   afterStart,
+  beginStart,
   claudeLoginPath,
+  isLatestStart,
   leavesLoginRunning,
   pastedCode,
   startOutlivedDialog,
@@ -40,11 +42,12 @@ export function ClaudeLoginDialog({
 
   useEffect(() => {
     let live = true;
+    const mine = beginStart(agent);
     void (async () => {
       try {
         const r = await fetch(claudeLoginPath(agent), { method: "POST" });
         const problem = await problemOf(r);
-        if (startOutlivedDialog(live, problem)) {
+        if (startOutlivedDialog(live, problem, isLatestStart(agent, mine))) {
           void fetch(claudeLoginPath(agent), { method: "DELETE" });
           return;
         }

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts

@@ -34,14 +34,33 @@ export function leavesLoginRunning(s: LoginStep): boolean {
   return s.step === "code";
 }
 
+// The newest start per agent. The minter keeps one login per agent and a
+// new start replaces it, so a late stop from an older start would end the
+// newer dialog's login.
+const latestStart = new Map<string, number>();
+
+// Marks a start as the agent's newest and returns its number.
+export function beginStart(agent: string): number {
+  const n = (latestStart.get(agent) ?? 0) + 1;
+  latestStart.set(agent, n);
+  return n;
+}
+
+// Whether `n` is still the agent's newest start.
+export function isLatestStart(agent: string, n: number): boolean {
+  return latestStart.get(agent) === n;
+}
+
 // Whether a start that answered after the dialog went away left a login
-// running: it did unless the start itself failed. The dialog stops it then,
-// since nothing is left to.
+// running that nothing else owns: it did unless the start itself failed or a
+// newer start has replaced it. The dialog stops it then, since nothing is
+// left to.
 export function startOutlivedDialog(
   dialogLive: boolean,
   problem: ProblemDetails | null,
+  latest: boolean,
 ): boolean {
-  return !dialogLive && problem === null;
+  return !dialogLive && problem === null && latest;
 }
 
 // What the code form may submit: the pasted code without surrounding

frontend/packages/swarm-ui/test/claude-login.test.mjs

@@ -6,7 +6,9 @@ import { test } from "node:test";
 import {
   afterCode,
   afterStart,
+  beginStart,
   claudeLoginPath,
+  isLatestStart,
   leavesLoginRunning,
   pastedCode,
   startOutlivedDialog,
@@ -49,10 +51,26 @@ test("only a login waiting for its code is stopped on close", () => {
   assert.equal(leavesLoginRunning({ step: "stored" }), false);
 });
 
-test("a start that answers after the dialog closed is stopped, unless it failed", () => {
-  assert.equal(startOutlivedDialog(false, null), true);
-  assert.equal(startOutlivedDialog(true, null), false);
-  assert.equal(startOutlivedDialog(false, { detail: "no minter" }), false);
+test("a start that answers after the dialog closed is stopped, unless it failed or was replaced", () => {
+  assert.equal(startOutlivedDialog(false, null, true), true);
+  assert.equal(startOutlivedDialog(true, null, true), false);
+  assert.equal(
+    startOutlivedDialog(false, { detail: "no minter" }, true),
+    false,
+  );
+  assert.equal(startOutlivedDialog(false, null, false), false);
+});
+
+test("only an agent's newest start counts as the latest", () => {
+  const first = beginStart("login-test-a");
+  assert.equal(isLatestStart("login-test-a", first), true);
+  const second = beginStart("login-test-a");
+  assert.equal(isLatestStart("login-test-a", first), false);
+  assert.equal(isLatestStart("login-test-a", second), true);
+  // Another agent's starts are counted on their own.
+  const other = beginStart("login-test-b");
+  assert.equal(isLatestStart("login-test-a", second), true);
+  assert.equal(isLatestStart("login-test-b", other), true);
 });
 
 test("a pasted code is trimmed, and a blank one is nothing", () => {