(sidebar): end a dropped session's running state when main drops it (#375)

.ai/contexts/session-state.md

@@ -558,6 +558,44 @@ response-ready (unchanged)" pin both branches of the decision — the icon
 slot's `session-icon--waiting`/`session-icon--response-ready` class and
 title, side by side, so a future reader finds the split intentional.
 
+#### A session main drops (issue #375)
+
+Main dropping a local-pty session (`process-exited`, then `activeSessions.delete`)
+is the one moment the renderer's running state for it has to end — in the
+sidebar row, the status bar and the activity state. The `pty-gone` purge in
+`updateRunningIndicators()` only runs when the running-set *signature* changes,
+so it could not be the only owner: a `cli-busy-state` or notification that lands
+after a poll already removed the id (a CLI stuck in an API retry loop keeps
+rewriting its title while it is killed) re-armed `cli-busy` on a row the
+signature gate then never revisited, and the status bar's `N running` was only
+redrawn by `loadProjects()`.
+
+- `onProcessExited` (`app.js`) removes the id from `activePtyIds`, calls
+  `dropLocalPtySession(id, 'process-exited')` for a non-remote row, and runs
+  `updateRunningIndicators()` at once instead of waiting for the next poll.
+- `dropLocalPtySession` (`session-activity.js`) is the single drop: live
+  subagents first (`clearActiveSubagentsFor`), then `purgeActivityFor`. The
+  `pty-gone` scan uses the same helper.
+- `updateRunningIndicators()` calls `renderDefaultStatus()` whenever the set
+  changed, so the status bar count follows `activePtyIds`.
+
+**Pty generation.** `wireSessionPty` (`main.js`) gives every spawn the next value of
+a monotonically increasing counter (`session.generation`). It is returned by all
+three `open-terminal` replies and sent as the fifth argument of every
+`process-exited` (the fork re-key's second send included). `app.js` records the
+generation of the last reply per id (`ptyGenerations`) and `handleProcessExited`
+ignores an exit older than it — no drop, no `closed`, no banner. An exit that
+lands while `openSession` awaits the reply is buffered (`pendingOpens`);
+`settlePtyOpen` then applies it unless the reply's generation is newer, so a
+stale exit never touches the new pty and a fast-failing launch still reads
+as exited. Chosen over suppressing the event in main because main cannot know
+which exit the renderer has already seen when it is delivered.
+
+Remote rows stay with the remote adapter (see "Row ownership"). Not covered: a
+busy signal that arrives after `process-exited` — main sends none, the PTY is
+gone. The pre-fix sequence is reasoned from the code, not reproduced live;
+`test/dropped-session-state.test.js` pins each step.
+
 ### The local-transcript adapter (step 4)
 
 `public/local-transcript-adapter.js` keeps one persistent

CHANGELOG.md

@@ -5,6 +5,7 @@ What changes for you in each release of Switchboard. How to write an entry: [doc
 ## Unreleased
 
 ### Fixed
+- A session that has exited no longer keeps a busy dot in the sidebar, and the status bar's running count drops as soon as the session ends instead of waiting for the next refresh. (#375)
 - Quitting, closing the window or reloading while a file in the file panel has unsaved edits now asks first, in any session, kept-aside tabs included: Save writes them (a file that changed on disk is not overwritten), Discard drops them, Cancel stays. If Switchboard does not answer within a few seconds, it closes anyway. (#373)
 - The IDE Emulation label in a session's terminal header now says whether the CLI is connected: it reads "IDE Emulation" only while it is, "IDE Emulation: waiting for CLI" when Switchboard is listening but the CLI has not connected, and "IDE Emulation: failed" when it could not start for that session, with the reason in its tooltip. A session whose IDE Emulation port was already taken no longer shows the label as if it worked. (#320)
 - On Windows, the file panel no longer opens or saves a credential file (such as one under `.ssh`) through its 8.3 short name or a `\\?\` path. (#390)

eslint.config.js

@@ -154,6 +154,7 @@ const rendererCrossFileGlobals = {
   currentActivitySeq: 'readonly',
   forgetActivitySeq: 'readonly',
   purgeActivityFor: 'readonly',
+  dropLocalPtySession: 'readonly',
   pruneRemoteActivityTimers: 'readonly',
   // public/session-activity.js's persisted per-session state — see .ai/contexts/session-state.md ("The local-pty adapter")
   localPtyState: 'readonly',

main.js

@@ -68,7 +68,7 @@
 }
 
 // Shell profiles → shell-profiles.js
 const { discoverShellProfiles, getShellProfiles, resolveShell, isWindows, isWslShell, windowsToWslPath, shellArgs, quoteArgvForShell } = require('./shell-profiles');
 const { startScheduler, refusedScheduleBinds, resolveScheduleSandbox, scheduleRegistry } = require('./schedule-runner');
 const { encodeProjectPath } = require('./encode-project-path');
 const { SETTING_DEFAULTS } = require('./public/setting-defaults');
@@ -478,8 +478,8 @@
     isInitialScanComplete, setInitialScanComplete,
   },
 });
 const { readSessionFile, readFolderFromFilesystem, refreshFolder, reconcileCacheFromFilesystem,
         buildProjectsFromCache, notifyRendererProjectsChanged, sendStatus, populateCacheViaWorker,
         scanFoldersViaWorker, setRemoteRoots, resolveFolderDir, isIndexingFinished } = sessionCache;
 const { resolveJsonlPath, enumerateSessionFiles, readSubagentMeta } = require('./read-session-file');
 
@@ -2198,7 +2198,11 @@
 }
 
 // see .ai/contexts/session-cache.md ("Remote hosts — tmux attach")
+let ptyGenerationCounter = 0;
+
+// see .ai/contexts/session-state.md ("A session main drops")
 function wireSessionPty(session, sessionId, ptyProcess) {
+  session.generation = ++ptyGenerationCounter;
   ptyProcess.onData(data => {
     const currentId = session.realSessionId || sessionId;
 
@@ -2301,12 +2305,12 @@
     const realId = session.realSessionId || sessionId;
     if (TRACE.on) trace('pty.exit', realId, { exitCode, signal: exitSignal, stopped, alsoUnder: realId !== sessionId ? sessionId : null, wasBusy: !!session._cliBusy, sent: !!(mainWindow && !mainWindow.isDestroyed()) });
     if (mainWindow && !mainWindow.isDestroyed()) {
-      mainWindow.webContents.send('process-exited', realId, exitCode, exitSignal, stopped);
+      mainWindow.webContents.send('process-exited', realId, exitCode, exitSignal, stopped, session.generation);
       // If a fork transition re-keyed this session under realId but the PTY
       // exited before transition detection ran, also notify the renderer for
       // the original sessionId so it doesn't stay stuck as "Running".
       if (realId !== sessionId && activeSessions.has(sessionId)) {
-        mainWindow.webContents.send('process-exited', sessionId, exitCode, exitSignal, stopped);
+        mainWindow.webContents.send('process-exited', sessionId, exitCode, exitSignal, stopped, session.generation);
       }
     }
     activeSessions.delete(realId);
@@ -2347,6 +2351,7 @@
       ok: true, reattached: true, sandbox: !!session.sandbox,
       mcpState: session.mcpError ? 'failed' : getMcpState(session.realSessionId || sessionId),
       mcpError: session.mcpError || null,
+      generation: session.generation,
     };
   }
 
@@ -2381,7 +2386,7 @@
       };
       activeSessions.set(sessionId, remoteSession);
       wireSessionPty(remoteSession, sessionId, attachResult.ptyProcess);
-      return { ok: true, reattached: false, remote: true, sandbox: false };
+      return { ok: true, reattached: false, remote: true, sandbox: false, generation: remoteSession.generation };
     }
   }
 
@@ -2441,7 +2446,7 @@
   // WSL profiles only work for plain terminals — Claude CLI sessions need the
   // Windows shell because session data lives on the Windows filesystem.
   const requestedProfile = resolveShell(effectiveProfileId);
   const useWslProfile = isWslShell(requestedProfile.path) && isPlainTerminal;
   const shellProfile = (isWslShell(requestedProfile.path) && !isPlainTerminal)
     ? resolveShell('auto')
     : requestedProfile;
@@ -2690,6 +2695,7 @@
     ok: true, reattached: false, sandbox: !!sessionOptions?.sandbox,
     mcpState: mcpError ? 'failed' : getMcpState(sessionId),
     mcpError,
+    generation: session.generation,
   };
 });
 

preload.js

@@ -111,7 +111,7 @@ contextBridge.exposeInMainWorld('api', {
     ipcRenderer.on('session-detected', (_event, tempId, realId) => callback(tempId, realId));
   },
   onProcessExited: (callback) => {
-    ipcRenderer.on('process-exited', (_event, sessionId, exitCode, signal, stopped) => callback(sessionId, exitCode, signal, stopped));
+    ipcRenderer.on('process-exited', (_event, sessionId, exitCode, signal, stopped, generation) => callback(sessionId, exitCode, signal, stopped, generation));
   },
   onTerminalNotification: (callback) => {
     ipcRenderer.on('terminal-notification', (_event, sessionId, message) => callback(sessionId, message));

public/app.js

@@ -125,6 +125,8 @@ let showTodayOnly = false;
 let cachedProjects = [];
 let cachedAllProjects = [];
 let activePtyIds = new Set();
+const ptyGenerations = new Map();
+const pendingOpens = new Map();
 let sortedOrder = []; // [{ projectPath, itemIds: [itemId, ...] }, ...] — single source of truth for sidebar order
 let activeTab = 'sessions';
 let visibleSessionCount = SETTING_DEFAULTS.visibleSessionCount;
@@ -498,7 +500,7 @@ window.api.onSessionForked((oldId, newId) => {
   pollActiveSessions();
 });
 
-window.api.onProcessExited((sessionId, exitCode, signal, stopped) => {
+function applyProcessExit(sessionId, exitCode, signal, stopped) {
   if (window.ATRACE) window.atrace('recv.process-exited', sessionId, { exitCode, signal, stopped });
   const entry = openSessions.get(sessionId);
   const session = sessionMap.get(sessionId);
@@ -509,6 +511,10 @@ window.api.onProcessExited((sessionId, exitCode, signal, stopped) => {
     return;
   }
   noteSessionExit(sessionId, exitCode, signal, stopped);
+  // see .ai/contexts/session-state.md ("A session main drops")
+  activePtyIds.delete(sessionId);
+  if (!sessionItemEl(sessionId)?.dataset.remoteAlias) dropLocalPtySession(sessionId, 'process-exited');
+  updateRunningIndicators();
   const exit = lastSessionExit(sessionId);
   if (entry) {
     entry.closed = true;
@@ -562,6 +568,37 @@ window.api.onProcessExited((sessionId, exitCode, signal, stopped) => {
   // Claude session exited → update persisted working set (entry.closed=true → excluded from set)
   schedulePersistWorkingSet();
   pollActiveSessions();
+}
+
+// see .ai/contexts/session-state.md ("A session main drops")
+function handleProcessExited(sessionId, exitCode, signal, stopped, generation) {
+  const recorded = ptyGenerations.get(sessionId);
+  if (typeof generation === 'number' && typeof recorded === 'number' && generation < recorded) return;
+  const pending = pendingOpens.get(sessionId);
+  if (pending) {
+    pending.push({ args: [sessionId, exitCode, signal, stopped], generation });
+    return;
+  }
+  applyProcessExit(sessionId, exitCode, signal, stopped);
+}
+
+function beginPtyOpen(sessionId) {
+  pendingOpens.set(sessionId, []);
+}
+
+function settlePtyOpen(sessionId, result) {
+  const buffered = pendingOpens.get(sessionId) || [];
+  pendingOpens.delete(sessionId);
+  const generation = result && result.generation;
+  if (typeof generation === 'number') ptyGenerations.set(sessionId, generation);
+  for (const exit of buffered) {
+    if (typeof generation === 'number' && typeof exit.generation === 'number' && exit.generation < generation) continue;
+    applyProcessExit(...exit.args);
+  }
+}
+
+window.api.onProcessExited((sessionId, exitCode, signal, stopped, generation) => {
+  handleProcessExited(sessionId, exitCode, signal, stopped, generation);
 });
 
 // --- Terminal notifications (iTerm2 OSC 9 — "needs attention") ---
@@ -956,9 +993,7 @@ function updateRunningIndicators() {
         // A stopped PTY can never emit subagent-completed (stop-session kills
         // the process; detectSubagentTransitions skips exited sessions), so
         // drop the live-subagent state now instead of waiting for the TTL.
-        clearActiveSubagentsFor(id);
-        // Runs after clearActiveSubagentsFor — see .ai/contexts/session-state.md ("The local-pty adapter")
-        purgeActivityFor(id, 'pty-gone');
+        dropLocalPtySession(id, 'pty-gone');
       }
       if (item.dataset.remoteAlias) setRemoteAttached(id, running);
       // local-pty takes over a row the user just opened — see .ai/contexts/session-state.md
@@ -976,6 +1011,7 @@ function updateRunningIndicators() {
       const dot = group.querySelector('.slug-group-dot');
       if (dot) dot.classList.toggle('running', hasRunning);
     });
+    renderDefaultStatus();
   }
 
   // Update grid card dots and status text — always run because sessionBusyState
@@ -1226,7 +1262,15 @@ async function openSession(session, customOptions, { automatic = false, live } =
   const resumeOptions = customOptions
     || (session.type === 'terminal' ? { type: 'terminal' } : await resolveDefaultSessionOptions({ projectPath }));
   forgetSessionExit(sessionId);
-  const result = await window.api.openTerminal(sessionId, projectPath, false, resumeOptions, entry.initialSize);
+  beginPtyOpen(sessionId);
+  let result;
+  try {
+    result = await window.api.openTerminal(sessionId, projectPath, false, resumeOptions, entry.initialSize);
+  } catch (err) {
+    settlePtyOpen(sessionId, null);
+    throw err;
+  }
+  settlePtyOpen(sessionId, result);
   if (!result.ok) {
     entry.terminal.write(`\r\nError: ${result.error}\r\n`);
     entry.closed = true;

public/session-activity.js

@@ -97,6 +97,12 @@ function purgeActivityFor(sessionId, via) {
   applyStateClasses(sessionId, createSessionState('local-pty').snapshot());
 }
 
+// see .ai/contexts/session-state.md ("A session main drops")
+function dropLocalPtySession(sessionId, via) {
+  clearActiveSubagentsFor(sessionId);
+  purgeActivityFor(sessionId, via);
+}
+
 // Central activity dispatcher. `via` is trace-only — see docs/activity-trace.md.
 // opts.armReady=false: going idle must not arm response-ready — see .ai/contexts/session-cache.md ("Remote hosts — busy spinner")
 function setActivity(sessionId, active, via, opts) {